Black Worcester is probably the oldest English pear still in use. It can be traced back to the early 16th century, and is probably much older than that.
Black Worcester pre-dates the trend towards the Continental sweet buttery-fleshed pears that became popular in Victorian England. This is not a pear you eat fresh, but rather one for the kitchen. Slow cooking transforms the fruits, and this is the definitive choice for traditional English stewed pears.