Named after the archbishop who advised King John and started the Minster, the De Grey Rooms were built in 1835 just outside the town's western wall near Bootham Bar (Gate). It is now owned by a preservation trust. It was made of Roman cement -- the architectural rage at that time -- before Portland cement became ubiquitous. The ancient Romans created cement out of lime and volcanic ash and some of their buildings (like the coliseum) still stand 2000 years later. About forty years before this building was erected, a Brit invented a process to produce a similar substance.
The building is home to many departments of the local government such as the tourist bureau.