As stated, Reynier rented a house at Voldersgracht in which he started an inn in order to make a better living for his family – and later on he ran a combination of an inn and a trade in fine art paintings. The inn was named the Flying fox, de Vliegende Vos. This name referred to his own first name Reynier and his last name Vos, both alluding to the old story about Reynard the Fox.
Patronimics [as in Jan’s son] being the standard in society and last names being a fairly new thing, he used the name Vos / Vosch in 1628 and later on in documents – however being an upmarket painting dealer and therefore a Guild member, he started to call himself Reynier Jansz Vermeer (1640). In his capacity as dealer in paintings Reynier among others traded in landscapes by Groenewegen. Some of the sketches in the Bramer album (made between 1642-1654 by Bramer) were copied from paintings in his trade collection.
Under the family name of Vos he had twice rented a house at Voldersgracht for use as an inn, and (with Montias) we accept that this was twice the same house. The first contract is lost but we do know the second contract, dated 1637. In another earlier document Vos is mentioned as living at Voldersgracht in 1635 as well, as caffa worker and innkeeper of The Flying Fox.
More research will be needed to find the exact setup of the present day house numbers 25 and 26. We know that the boy Johannes Vermeer indeed lived there (at least between 1635 and up until 1641). He may have been born there as well.