In 1215 the Oxford to Aylesbury Road was diverted from its original route between the Church and the Prebendal, to its current path along North Street making New Thame one of the principal markets in the region. King John (1199-1216) granted the Tuesday market a royal charter in 1215, increasing the bishop’s income from tolls on goods brought into the town, and rents on market stalls and burgage plots.

Tradesmen such as ironmongers, tanners, carpenters, vintners, brewers, fishmongers, butchers and bakers were attracted to the town. Four of these successful merchants served as churchwardens responsible for collecting and spending church revenue.

The Bird Cage was built around 1300 with an open lower storey used by market traders, with the front on the left side of the current building opening directly onto the marketplace.