The Assizes were an important part of Lancaster life for many centuries. They were the highest court in England, dealing with the most serious cases. Lancaster was the site of the Assizes for the whole of Lancashire after 1362 and they were held two or three times a year, often in spring and autumn.

In 1827 it was noted that, to deal with 92 criminal cases and 242 civil ones, 116 barristers had come to Lancaster, doubtless along with juniors and staff.