ISAIÀ of Pisa. - Sculptor active in Rome and Naples around the mid-15th century. In 1447 in Rome he is commissioned, as successor to Filarete, to complete the tomb of Antonio Martínez Chiaves, Cardinal of Portugal (now fragmentary in S. Giovanni in Laterano), and in the same year he participates in the works for the burial of Pope Eugene IV (now in S. Salvatore in Lauro, in the cloister).
Projects for the crowning of the façade of Orvieto Cathedral (unexecuted) date from 1450-51. In 1456-58 he works in Naples on the Arch of Castel Nuovo; in 1460 he is again in Rome at the service of Pope Pius II, for whom he executes the tabernacle of S. Andrea for St Peter’s, now fragmentary in the Vatican Grottoes. Among his other works are the lavabo of S. Maria Maggiore and the relief on the architrave of S. Marco. His art derives from Pisan sculpture, whose themes he continues to echo; yet his weak but clearly individual artistic personality wavers between various tendencies, ranging from a love of the antique to memories of Donatello, with results marked by plastic vigour and insistent calligraphic traits. I. of P. is the father of the sculptor Gian Cristoforo Romano.