The East Block on Parliament Hill was built in two stages. The main section went up in the mid-1800s at the same time as the West Block and the original Centre Block. Then, in 1910, a wing was added at the rear. The purpose, style and appearance of the 1910 wing were quite different from those of the earlier structures. The original East Block was once the domain of some famous Canadians. Indeed, Sir John A. Macdonald and Sir George-Étienne Cartier had offices in this block, as did a number of Governors General and members of the Privy Council.
When the 1910 wing was added, in effect linking the two ends of the original building and enclosing a courtyard, the intent was to provide space for government employees, not legislators and their staff. Consequently, this section is less ornate than the rest of the building. Nevertheless, parliamentary functions gradually encroached.
The 1910 wing had 6 massive vaults, originally used for storing the nation's financial treasures before the Bank of Canada was constructed. Rumours have circulated for years that gold was once kept here. The vaults have been converted to office space, but the original doors have been preserved.