At Pisa then we have an artistic sphere which might well have produced Niccolò di Pisa, even without the influences of the south. We will, as far as the few inscriptions and documents allow, see who were the members of this Masonic lodge, which had painters before even the rise of the Siena school, and whose building was the earliest model for the Romanesque style. Bonanno, who assisted in the building of the tower, was more famous in the guild for his metal working than for architecture and marble sculpture. The fame of the bronze doors of the Duomo which he cast is now only traditionary, as they were destroyed by the fire on October 25, 1596. The antique inscription has been preserved, and proves that in 1180 Bonanno cast the doors, which had taken him a year to model, and that a certain "Benedict" was _operarius_ at the time.[172] Bonanno's successor as a master in bronze was a certain Bartolommeo di Pisa, who was, like Bonanno, sculptor, architect, and metal-worker. He was much patronized by the Emperor Frederic, for whom he built the palace at Foggia, and made a tomb. He seems to have been a famous bell-caster; there are inscriptions quoted by Morrona,[173] which have been found on bells in the leaning tower of Pisa, the bells of the churches of St. Francis at Assisi, S. Francesco at Siena, S. Paolo a Ripa d'Arno, and S. Cosimo at Pisa, S. Michele at Lucca, etc. Sometimes his name stands alone; sometimes one of his sons, Lotteringo or Andreotti, is associated with him. Later we find the sons' names alone in independent works, and then with the distinctive title of _Magister_. Through this group of Pisan Masters a special connection was established with the south, a link which might account for Pietro, the father of Niccolò, being called Pietro da Apulia, for there certainly was an offshoot of the Pisan lodge in that part. Bonanno of Pisa cast the famous bronze doors of Monreale; Bartolommeo was at Foggia; and his son, Magister Lotoringus, passed most of his life at Cefalù, where his name appears on a bell dated A.D. 1263. The Emperor Frederic, his father's patron, nationalized him in Cefalù, and after ten years of residence, in 1242 he gave him permission to take a wife from Castro-Vetere in Calabria. Other metal-workers and bell-casters at Pisa were a Nanni, a Pardo Nardi, and others whose names appear inscribed in the twelfth century. I do not know whether the Angelo Rossi, whose name with the date 1173 is on a sculptured bell once in the church of S. Giovanni in Pisa (now at Villa di Pugnano), was a fellow-pupil or scholar of Bonanno's. His work is less artistic and masterly.