Birr started life as a 6th-century monastic site founded by St Brendan. By 1208 the town had acquired an Anglo-Norman castle, home of the O’Carroll clan who reigned over the surrounding territory.
During the Plantation of 1620, the castle and estate were given to Sir Laurence Parsons, who changed the town’s fate by carefully laying out streets, establishing a glass factory and issuing a decree that anyone who ‘cast dunge rubbidge filth or sweepings in the forestreet’ would be fined four pennies. He also banned barmaids, sentencing any woman caught serving beer to the stocks (obviously he was a Philistine). The castle has remained in the family for 14 generations, and the present earl and his wife still live on the estate.