Pisa Cathedral is a typical representative of Italian Roman church architecture, located in Pisa, Italy. The cathedral was built in 1063 to commemorate the Virgin Mary. It is a rectangular Latin cross. The cathedral has three passages, two on each side of the main hall. The church also preserves the remains of Saint Ranieri, the patron of Pisa, and the tomb of the Roman emperor Henry VII. During the Tuscany calendar reform from the tenth century to 1749, Pisa used its own calendar, and the cathedral was used to determine the beginning of the Pisa New Year. The cathedral has tilted slightly since it was built, but not so much as the bell tower.