Notable buildings in the town include the castle , a courthouse built in 1614 , St Mary 's parish church , and the town gaol . Notable buildings in the town include the castle , a courthouse built in 1614 , the fourteenth century St Mary 's parish church , the town gaol , the 14th century Tudor Rose ( one of the oldest original timber-framed buildings in Britain ) and the Bulls Head Inn ( built in 1472 , which General Thomas Mytton made his headquarters during the `` Siege of Beaumaris '' during the second English Civil War in 1648 ) .