For the first century or two of Boston's history this was a place to pasture your cows (no more than 70 at a time), drill soldiers (the British Regulars camped here) attend the occasional public hanging (for offenses such as being a witch, or being a Quaker), or perhaps simply take a nice walk... near all the cows and hanging. The British left the camp when they fled the city in 1776. Public hanging ended in 1817. The cows were banned in 1830. You can still take a walk there, however, but what's the point, without the cows?