As far as the Bible and the best guesstimates of historians allow us to know, Jesus Christ was born in a humble barn in the Judean town of Bethlehem 2020 years ago.
It was a time when the huge military might of the Roman Empire dominated Europe and the middle east.
Jesus of course eventually went on to become a symbol of rebellion against the Jewish church leaders and against the tyrannical Roman government, eventually being crucified on the cross at the orders of the Roman governor of Judea, Pontius Pilate.
This may all seem to be a world away from away London. But in fact, the Roman Empire which had spread to reach Judea in the east, was about to direct its awesome power far to the west, to Britain.
And just a few short years after Jesus is said to have died on the cross around the year 33 CE, a huge Roman army crossed the channel and invaded Britain, intent of gaining glory for the Roman Emperor Claudius.
It was very soon after this that the very first true city of London was begun.
But far from being anything to do with religion or Jesus, this first London was in fact a shoppers' paradise, bustling with traders and markets and packed with a multi-cultural population from right across the known world.
Not so different from today you might say.
As London's great author, Peter Ackroyd, once wrote in his amazing book 'London Under', there's as much of London under the ground as there is above it - another entire city beneath surface makes up sewers, tunnels' electricity power stations, hidden bunkers, cable-networks, tube stations and basements.
And hidden in amongst this vast subterranean city, submerged in the layers of silt and mud that have built up over generations, it's possible to travel back through time to find the hidden remains of the first London. The city that began to emerge from the Thames valley mud, not long after Jesus was crucified and his legend began to spread.
Known as Londinium by the Romans, the city quickly became the grandest settlement that the far-flung Roman province of Britannia had to offer. As four Roman legions swept across Britain, making treaties with the Celtic tribes who would make deals with them and brutally conquering those that wouldn't, London began to grow.
To conquer a wild and untamed country would have required huge amounts of supplies. Food, weapons, wine, timber, tools. It quickly became clear that the Thames could be used as a brilliant way sail these goods into the heart of the province and that the low-lying settlements on its banks were the best places to unload them.
International traders from across the empire began to land their goods in the city, and everything needed for an international port began to grow up here. Just as the Roman towns of Biblical Judea would have been a melting pot of Jews and gentiles, , Egyptians Phoenicians, Greeks and Romans, so London was a migrant city of Germans, Gauls, Italians, Spaniards and many more besides.
Having made the hazardous crossing across the English Channel, traders would have moored their ships at wharves built from timbers driven into the muddy river banks. Pieces of them have survived near Lower Thames Street.
Stepping off the ships, visitors would have made their way inland through narrow streets leading up from the wharf, past a hotchpotch of taverns, blacksmiths' shops, potters' stalls, food shops and brothels.
At the top of what is now Cornhill, you would have come upon a junction of Roman roads leading to the nearby towns of Silchester (Calleva) and St Albans (Verulamium).
The first London bridge
A wooden bridge, built by the army, would have led over to the southern bank of the river where settlements also began to spring up on islands amidst the creeks of Southwark.
As you walked through the town, everyone would have been trying to sell you something - whether it be wine, food, clothes or some company for the night. The earliest writings make clear that this was a rough and ready frontier city in the early days with something of a cutthroat atmosphere - something a bit like a wild west town. Needless to say - as in today's London. you would have had to watch your back.
Buzzing city squares
As you wandered north of the river, you would have found the streets laid out in a uniform grid like most Roman towns, and in the middle, a buzzing market square where traders and businessmen would have met to make their deals. Even in the early days this was a city built on commerce.
London grew quickly as the conquest of the province went ahead. There was one moment when it looked as if all might be lost. The British rebel queen, Boudicca, famously bunt the city to the ground and massacred its population in AD 60, along with St Albans and Colchester. She had been driven to fight back after her tribe suffered abuses at the hands of Roman tax gatherers and her daughters were raped.
Don't mess with Rome
But the Roman venture-capitalists were not to be deterred and they hit back hard, smashing the tribes in a huge battle led by the general Suetonius and slaughtering thousands. London was re-built, bigger and better and became the capital of the province. It was a clear message that you didn't mess with Rome.
A military fort was added in the north-west of the city with a garrison of soldiers, an amphitheatre, bath houses and all the mod-cons of a civilised Roman city. It would have been a bit like a mini Pompeii.
Many in the city would have prospered from trade, and the remains of ornate houses have been found with beautifully decorated mosaic floors, bath houses and underfloor heating.
The beautiful jewellery, ornate pottery, gold coins and glasswear which can be seen in the Museum of London, attests to wealth that London's success generated for some.
So it seems strange that there are so few visible Roman remains of this ancient city above the surface. It's certainly no Pompeii or Herculaneam today, not bursting with pillars, temples and colourful mosaics which fire the imagination with all the glamour and barbarity of ancient Rome.
But the fact you have to hunt a bit to seek out London's ancient remains, makes them all the more intriguing and worth finding out, and your imagination fills in the gaps.
So what exactly will you be rewarded with if you spend a couple of hours seeking out the lost ancient city?
Gladiators at the Guildhall?
Well, the Guildhall is a good place to start. If you step into the Guildhall square off Basinghall Street in the City, you'll see a semi-circle marked in black on the paving stones.
This doesn't give much away, but if you step through the doors of the Guildhall art gallery itself, you'll soon see signs guiding you down to the basement.
Here you can see all that remains of London's very own Roman colosseum - its lost Roman amphitheatre.
There's not loads left of the stone structure of the oval shaped stadium, but after it was excavated in the 1990s, designers combined the remaining stone foundations with an clever light display which allows you to see the banks of seats around the extent of the stadium where Romano-British audiences would once have laughed, jeered, cheered and booed.
The amphitheatre was first built as a simple wood and earth structure around AD 70 and then re-built much more substantially in stone about 120 CE.
You've probably all seen films like Gladiator and Spartacus where heavily armoured bloodthirsty warriors battle it out to the death in front of audiences baying for blood in the great amphitheatres of the Roman Empire, such as the huge Colosseum in Rome.
But did this kind of brutality ever actually take place in London? The truth is that despite all the archaeological digs and research that has taken place, we just don't know.
There are indications like pieces of jewellery and amulets depicting gladiators that have been found buried in London, but no direct evidence that gladiators fought and died here.
So If not that, then what on earth would the amphitheatre have been used for? Certainly it would have been home to beast hunts where wild animals - the more exotic the better - were pitted against each other in gruesome fights, or hunted down by trappers using spears, slings and bows.
But it might also have been used for religious activities, public executions and even public meetings - much like a council chamber.
But one of the most intriguing discoveries from Roman London tells a different story.
The mystery of the skulls
In 1988 when the amphitheatre was being dug up, archaeologists discovered some 39 well-preserved skills buried in the earth nearby. They had hit upon a Roman death pit, an intriguing mystery to say he least.
Roman law forbade burying people within the city walls, so the question was, what on earth were such a large number of skulls doing inside the old Roman city?
Some 36 of the skulls were definitely from men, and fairly young men at that - most between 18-35 years old
More incredibly, most of the skulls had blunt-force trauma injuries sustained at the time of death, and five had sharp-force weapon injuries, which could have been caused by anything from a Roman soldier's sword to a weapon wielded by a gladiator. These people - whoever they were, had died in the most brutal of ways.
Other evidence such as a dog bite on one skull, meant it was likely the bones had spent time scattered in the open - suggesting they were thrown into open pits rather than being properly buried. This suggests very clearly these were people who were dispensable such as criminals or down-and-outs - the kinds of people who sometimes did become gladiators.
We can't know for certain, but it does seem incredibly likely these were the skulls of gladiators who had died after falling in bloody combat in the Roman amphitheatre. Spectators may even have decided their fate by giving the famous 'thumbs up' or 'thumbs down' signal which some believe encouraged the gladiators to deliver the final blow.
Other possibilities are that the heads could have been from criminals who were brutally executed and thrown into pits - evidence of this kind of practice has been found elsewhere in the Roman empire.
Finally - and even more strangely, it's been suggested these could have been victims of headhunting - the practice where Roman soldiers ruthlessly hunted down enemies and then decapitated them, removing their heads to be displayed as trophies.
This horrific practice again is known to have happened elsewhere in the Roman empire, much as it happened in later medieval times when the heads of traitors were displayed stakes outside the tower of London or on London Bridge.
Either way, whoever these people were, they met a horrible death in the heart of the ancient city of Londinium.
Gods and mysteries
Our second 2,000-year-old Roman mystery is also hidden deep under ground.
You can take a lift down deep into the basement of the recently-built headquarters of the media company, Bloomberg at 3 Queen Victoria Street.
As you enter the space, you can her some men spookily chanting in the background - which on a closer listen appears to be in Latin.
Ahead of you you can see the eerily-lit remains of low walls shrouded by a fake mist, stretching out in front of you as you walk forward tentatively into the semi-darkness.
So what is this underground chamber? A dungeon? A prison? A burial chamber?
In fact this eerie reconstruction was once a strange temple, to an ancient God called Mithras. It's one of the strangest and most enigmatic cults in all of Roman religion and even to this day, little is known about the long-lost ceremonies that once went on inside this place.
It's seven metres underground today and just slightly to the West of the site where archaeologists first discovered the lost Roman temple in 1952. At that time it was a sensational discovery on an old wartime bombsite, and people flocked from all over the UK to see it.
On some days more than 30,000 people queued up to see the ruin. But after the excavation the developer arranged for the temple to be dismantled and moved elsewhere. When Bloomberg bough the site in 2010, the firm decided it wanted to take responsibility for moving the temple much closer to its original site and recreating the ambience and atmosphere of what it would have been like in ancient times.
The story goes in ancient myth that the God Mithras slayed a bull and it's possible that worshippers at the temple also killed bulls or at least took part in a dark ceremony that simulated killing one.
Certainly at the centre of the cult was the idea of Mithras slaying the bull but we're not absolutely sure what the significance of it was. Many ancient historians believe it was some kind of dedication to fertility.
More than 100 mithraeum have been discovered in the Roman world, meaning it was a popular, but niche, cult. The temple had a central nave where it is thought the mysteries of the ceremonies took place.
There were steps down into the temple and no windows, so it would have been eerily dark and lit by candles and oil lamps. This was probably meant to recreate the conditions of a cave where Mithras was thought to have slayed the bull and it no-doubt added a sense off fear and mystery to the worship of the God.
Mithraeum are often discovered on ancient Roman military forts suggesting the cult was very popular with soldiers and may have involved a strong sense of brotherhood and morality, a bit like the later Knights Templar of Free Masons.
In the temple itself at one end in a rounded apse there would have stood a statue of Mithras. Incredibly, the amazingly preserved stone head of the God was found by archaeologists at the site in 1954.
Once you've finished your underground experience you can marvel at a display of 600 2,000-year-old artefacts that were dug up near the site of the temple. These amazing objects were part of thousands discovered in excavations on the banks of the underground Walbrook River between 2010-14 - which once ran right through Roman London.
The muddy conditions of the river banks preserved the artefacts in incredible condition from what would have been the very heart of Roman London. They included coins, pottery, shoes, lucky charms and an amazing amber gladiator amulet.
The objects suggest small workshop,s homes and a bakery were all crammed into this busy area of the town along the banks of the old river.
The first Londoners
One of the most amazing discoveries from the Walbrook digs gave the most revealing insight into what Londoners were like 2,000 years ago because, incredibly, it preserved their actual words.
A huge stash of some 405 Roman wax writing tablets was found in the muddy earth.
These were basically wooden frames with a wax layer on that would have been scratched with a stylus - a primitive pen usually made of ivory, bone or wood. The wax layers from the tablets had long since disappeared, but thankfully, many of the Roman writers had pressed so hard that the words were actually scratched into the wooden backings.
Careful reconstruction of these words has revealed some of the best evidence we have for how Romans lived 2,000 years ago in Britain.
It also reveals the very cosmopolitan nature of Roman London and the fact that it was very much a frontier town on the edge of the empire.
The tablets contained the very very first written mention of the town of Londinium ever discovered - it's from a tablet that can be dated to between 65 and 80 AD.
There's a tablet dated to between AD 43 and AD 53, showing that the site of Londiunium was already being occupied less than a decade after the Romans invaded and only a few years after Jesus's death.
Many of the tablets are financial calculations or trading agreements so we can tell that the earliest function of Londinium was as a centre of trade where goods would have been shipped in and out of Britannia along the River Thames.
Some tablets even show people practising the Roman alphabet which suggests there may have been a school somewhere nearby where Latin was taught.
The tablets also give us an amazing insights into the nationalities and occupations of the inhabitants of the Roman city.
They have revealed the names of nearly 100 people, from a cooper, brewer and judge, to soldiers, slaves and freedmen and show that many of the traders and soldiers who lived in the city were from Gaul (now France) or parts of Germania (Germany).
It's been suggested the tablets show London was very much like a wild-west frontier town on the fringe of he Roman Empire. It was somewhere people were rushing to to try to make their fortunes and get whatever profit they could make out of the new Roman province.
There's a couple of amazing statues that you should see in London. Though they are not actually Roman, they really help to tell the fascinating story of the city.The first is of the great Roman Emperor Trajan.
Its location is the most important thing because it sits just next to one of the most impressive sections of Roman wall from the old city just to the north of the Tower of London.
The emperor stands, hand aloft in a regal salute, as if surveying modern London as it grows out of the ancient city. Trajan never visited Britain, but he did preside over a golden age of the Roman empire when it extended to its largest ever reach and the province of Britain had largely been pacified after the struggles and rebellions that dogged Roman rule in earlier years.
It was during his rule in the early years of the second century that Londonium was at its height.
And on the subject of rebellions, you should also look for the incredible statue of Boudicca and her daughters riding a magnificent chariot which sits at one end of Westminster Bridge.
It's really easy to walk past this statue in the hubub of modern life, but it's a great work of art. A testament to the huge impact the rebellion made on Britain and to the way Boudicca has come to be seen as a symbol of British power and independence.
The great wall
A great way to seek out some of lost London is to walk around what's let of its massive Roman walls.
It was pretty normal for large Roman towns and forts to be surrounded by walls - first built with in wood and earth and later replaced by huge carved blocks of stone. Building them might seem fairly straightforward, but make no bones about it, in Roman times it was a major achievement.
The wall was a defence against rebels and raiders but perhaps more than that, was a sign of prestige and power.
It wasn't until the late second/early third centuries that walls started to be built the around the whole settlement. The walls were around three kilometres long and six metres high and included grand gateways at the places where the main roads entered the city.
This was a time when Roman Britain was fast becoming more unsettled. Raiders from Scotland known as the Picts and pirates from Germany known as Saxons began raiding deeper into the Roman province as instability within the empire meant garrisons of troops were weakened as they were bled away from Britain to serve elsewhere. In this growing chaos the walls would have become a place of refuge from attack.
Today you can see some impressive remains of the once-mighty walls. One of the best sections is just north of the Tower of London by the statue of Trajan, another just a little further north at Coopers Gate. Towered over by modern buildings,these stone remnants are an evocative reminder of how much the city has changed in 2,000 years.
Right near the Museum of London on the west side of Noble Street you can see a section of the old wall with the foundations of a corner turret. This was originally part of a military fort at Cripplegate before being incorporated into the main walls of the north-west corner of the city. A further well-preserved stretch lies in gardens to the east of the Museum of London.
The foundations of an opulent Roman town house with a bath house lie under a building in Billingsgate and are sometimes opened on special occasions such as the Open House weekends in September.
Treasures on display
The Museum of London at the Barbican has a truly amazing collection of objects from Roman London including gravestones, beautifully designed pottery, intricate jewellery, glassware and statuettes of Roman gods. This is all collected together in a very well presented and illustrated display explaining the history of Londinium.
The British Museum also has many stunning objects from Roman London and Roman Britain in its incredible Roman Britain gallery, There are also sections of some really good Romano-British mosaic floors.
A journey back 2,000 years to the London that existed in Biblical times is fascinating and surprising. So much has been lost yet so many fascinating clues remain. And ironically, as the city began to prosper in the years after Jesus' death, soon his followers were spreading the story of his incredible life to the city and the first Christian churches were being founded.
In 2006, archaeologists uncovered a series of graves right next to the site of the modern St Martin-In-The Fields church off Trafalgar Square. The graves were all laid out east to west - the traditional direction of Christian burials. One of them dated to around 400 CE, showing that Christianity was beginning to establish itself in London and Britain at this very early date.
Of course this was just the beginning. Churches and altars would eventually spring up all over the city which is today still full of spires. The first version of St Paul's Cathedral was one of the earliest and best.
Jesus lived just before London was established - though there is a myth that he did visit Britain. But his influence took over the city. London prospered in the Middle Ages and into the modern age as a primarily Christian city.
The 2000-year-old story of the rebel the Romans crucified in Judea, ironically came to be the power base of the version of the Roman Empire that has been handed down to us to this day
If you have a story about London's past, please email firstname.lastname@example.org