St. Leonards itself wasn't a church as its name might suggest. Its primary function was as a hospital - although the role of the church in providing healthcare was a close one. Today, we would think it odd if a hospital was involved in the execution of prisoners but this is to judge a previous age by our own standards. In fact, there were both practical and ethical bases that could aid the hospital's work. In some instances, repentant criminals could be given a decent Christian burial but as the records attest, many were given over to the city's anatomists for dissection. As the bodies of executed criminals were the only legal source for anatomists to study the human body, and given that long term storage of bodies was impossible in age before refrigeration, it made eminent sense for executions to be carried out near to a hospital so that their fresh corpses could be dissected by aspiring surgeons.
Today, the name of St. Leonards still lives on in the name of a hospice and the ruins of the original building still stand and are open to visitors.