St William's College was built circa 1465 to provide accommodation for the chantry priests of York Minster. During the Civil War, it housed the Royal Mint.

Image 1

Photo as per caption. Opens larger version.
The stone setts of College Street, with the southwest elevation of St William's College beyond.

According to the City of York Council, St William's College is:

the most sophisticated timber-framed building in the city

Source: The City of York Council's Conservation Area Appraisal for York Central Historic Core - Character Area 9: Minster Precinct.
(The source document is undated, but the pdf file properties include a creation date of 2 June, 2014.)