The ground floor is modelled on the Theatre of Marcellus and the Colosseum in Rome. It consists in a succession of Doric columns supporting an entablature and is layered over a series of arches resting on pillars. The combination of columns layered over an arcade had been proposed by Bramante for the Palazzo di Giustizia (unexecuted), and was employed by Antonio da Sangallo the younger for the courtyard of Palazzo Farnese (begun 1517). In adopting the solution for the Marciana Library, Sansovino was faithfully adhering to the recommendation of Leon Battista Alberti that in larger structures the column, inherited from Greek architecture, should only support an entablature, whereas the arch, inherited from Roman mural construction, should be supported on square pillars so that the resulting arcade appears to be the residual of a wall open and discontinued in several places.