SU1332 : Old Sarum Schoolboy history lessons portrayed Old Sarum as the quintessential 'Rotten Borough', a place with its population shrunk to so few voters it was virtually 'in the pocket' of the landowner. Thus William Pitt the Elder (1708-78) entered Parliament in 1735, becoming Prime Minister from 1766-68. It took the Reform Act of 1832 to snuff out this kind of constituency.