Under the Medicis a great age of palazzo building among the banking and merchant families began. The Strozzi built the finest such palace in the city (begun ca. 1489), in the heart of the old quarter, designed and executed by Benedetto da Maiano, Giuliano da Sangallo and Il Cronaca; the Palazzo Strozzi is grandiose, severe and monumental and was loosely based on the Palazzo dei Priori. In 1489 Giuliano and Antonio da Sangallo made a wooden model for Filippo Strozzi's new palace in Florence, subsequently built (1489-1504) under Cronaca's direction. The model (Florence, Pal. Strozzi) establishes the basic, bilaterally symmetrical plan but has a lower, unvaulted main storey, a plainer bracket cornice and façade masonry graduated (as at the Palazzo Medici) from large rounded blocks on the ground-floor to smooth ashlar at the very top.