Guazetta's peculiar line was laying foundations and devising complicated scaffolding. He also made the presses of the sacristy. He was perhaps not enough of a builder to hold the office of chief, for in 1375 this pair resigned in favour of Francesco Salvetti and Taddeo Ristori. Salvetti, however, very soon renounced office, preferring to remain in the guild on a simple salary, rather than incur responsibilities.[259] Then Francesco Talenti's son Simone, who had by this time become a _Magister_, was put in his place with Taddeo Ristori. Their reign lasted till 1388, when Michele, son of Giovanni, son of Lapo, son of Ghino, was elected. In his time the pilasters of the tribune were begun. In 1404 Ambrogio's son Giovanni was elected _capo maestro_. Here is the part of the entry of the _Deliberation_, November 17, 1404--"Operaris ... elegerunt et nominaverunt et deputaverunt in caput magister dicte opere Sancte Reparata providum virum Johannem Ambroxii, etc. etc., cum salario florenum otto, pro quolibet mense cum auctoritate, balia et potestate usitate et consueta."--_Delib._ xlix. 28. Another deliberation, dated June 17, 1415, states that "Johannem Ambroxii caput magister" shall give the order for the species and form of the bricks for some special part. Giovanni, the last of the Campione school whom we can register, was deposed for old age, and Baptista Antoni elected in his stead. He was probably the son of Antonio, the Grand Master mentioned above. Giovanni had not always time to carry out his own designs. In 1408 we find that Magister Niccolao, surnamed Pela, took the contract to carve in marble the doorway near the chapel of the crucifix, which was designed by "Johannem Ambroxii, caput magistrum." It is rich with vines and other ornaments. Niccolao did not push the work, however, and in May 1408 the _Opera_ decided that he owed the guild the sum of twenty-five florins for breaking his contract. The number of different minds each leading the works in his own department is bewildering. The beautiful door called the Mandorla, so rich and elegant in sculpture, which is often said to have been executed by Jacopo della Quercia, was in reality the work of Nanni di Antonio di Banco. The books of the _Opera_ register, on June 28, 1418, a payment of twenty florins on account to Nanni for this doorway, and in 1421 the last payment was made on the completion of the work. Nanni was a favourite scholar of Donatello; he was a person of good birth, who matriculated in the _Arte dei Maestri di Pietra_ on February 2, 1405, and proved his membership by sculpturing the four patron saints of the Masonic Guild on Or San Michele. We further find in this precious collection of documents that Magister Jacopo di Lapo Cavacciani made a model for a shaft; that Nato di Cenni and Jacopo di Polo were, in August 1357, engaged to make the bases of the columns, and that time after time different Masters were called on to make plans for chapels, windows, doors, etc.