The present Basilica of San Clemente was built near the conclusion of the Investiture Controversy, in the early decades of the 12th century. The mosaic in the apse represents the Church in the form of a vine that springs from the Cross of Christ. It is one of the most remarkable works of art in Rome, both for its beauty and for the depth of its theological and ecclesiological meaning, reflecting the ideals of the reform of the 11th and 12th centuries.