A native of Siena, this famous sculptor and architect was born on the 21st of December, 1391. He was son of a certain Tommaso, surnamed _Minella_ and had two brothers, Antonio and Giovanni (both workers in wood), the latter of whom became a Franciscan monk, and Rector of the Hospital of Sta. Croce. Pietro was a favourite pupil of Giacomo della Quercia, who left him ten florins in his will; and he worked with that great master on the famous Font in the Baptistery. From 1431 to 1433, he was Capo-maestro of the Opera del Duomo at Orvieto, and with his brother Antonio, executed some works there in intarsia on the stalls. In 1437, Quercia gave him some commissions in connection with the Loggia di S. Paolo, and in 1439 he was employed to make the choir for the Chapel of the Hospital of Sta. Maria della Scala. Out of this much litigation arose, which was settled by the giving of a dowry to his daughter.[159] In 1441, he and his brother Antonio were commissioned to make a new Bishops’ Throne for the Cathedral at Orvieto,[160] adorned with figures of SS. John and Costanzo; but apparently, whether for want of funds or for what reason does not appear, the work was never completed.[161] He remained at Orvieto until March, 1444, when he returned to Siena, where he had been commissioned by the Council to execute further work on the Loggia di S. Paolo.[162] In August of that year he was in treaty to go back to Orvieto, and we find a document, showing that he asked in payment for his services 120 ducats and a house, but agreed to accept 110 without the house, arranging to come to Orvieto about the middle of October to complete his bargain.[163] In September, however, he was promised by the _Camarlingo_ (perhaps the Treasurer) of the Opera del Duomo at Siena, the post of Capo-maestro there. This appointment, however, he did not at first obtain, though he was employed on the tomb of Carlo Bartoli, Bishop of Siena, for which he received, as his share, a sum of 38 lire 8 soldi;[164] and in the following year on the Chapel of S. Crescenzio in the Duomo.[165] At last, in 1447, he was appointed Capo-maestro, and during his occupation of the post, he designed the Church of S. Ansano. He died in August, 1458, having married Cristofora, daughter of Maestro Pannucci, surnamed _Cinquino_, and had by her three sons--Tone (Canon of the Duomo), Niccolo, and Sano, who died in 1498, having married Polissena, daughter of Arnoldo di Fortunato, by whom he had six sons. 17. 1450. _Nastagio di Guasparre._ 18. 1450. _Bartolomeo di Mariano_, called “_Il Mandriano_.” 19. 1451. _Guasparre d’Agostino._