The Laurentian Library was commissioned in 1523 and construction began in 1525; however, when Michelangelo left Florence in 1534, only the walls of the reading room were complete. It was then continued by Tribolo, Vasari, and Ammannati based on plans and verbal instructions from Michelangelo. The library opened by 1571. In this way, the library integrates parts executed by Michelangelo with others built much later in an interpretation of his instructions. The Laurentian Library is one of Michelangelo's most important architectural achievements. Even Michelangelo's contemporaries realized that the innovations and use of space in the Laurentian Library were revolutionary.