Pope Leo X died in 1521, to be succeeded briefly by the austere Adrian VI, then his cousin Giulio Medici as Pope Clement VII.[43] In 1524 Michelangelo received an architectural commission from the Medici pope for the Laurentian Library at San Lorenzos Church.[35] He designed both the interior of the library itself and its vestibule, a building which utilises architectural forms with such dynamic effect that it is seen as the forerunner of Baroque architecture. It was left to assistants to interpret his plans and carry out instruction. The library was not opened until 1571 and the vestibule remained incomplete until 1904.[44]