For whatever reason, the main gates in York's city walls are called bars. They were toll gates for entry to and exit from the city as well as being part of the defensive structures for the place. The name Micklegate is derived from Mykill and Gata so the name means Great Street and the gate was where royalty entered the city. That made it a prestigious entrance and the photo shows the top of the building as seen from the Blossom Street side, from the outside of the city walls in other words. In fact, it looks less impressive from the other side though that has gained a crest too so it isn't devoid of decoration either. There was a time when the upper stories of the gatehouse were used as living quarters but they now are used to house a museum.