In April 1422 we find Maestro Piero di Beltrami da Biscione and his Lombard companions arranging with the _Opera_ for the purchase and cutting of marbles and travertine. In September 1444 Guglielmo di Como and his brother Pietro da Como were commissioned to make a mausoleum in the Duomo for the Bishop of Siena. A contemporary of theirs was Giuliano da Como, who was of such repute in the guild, that the Council of the _Opera_, "considering the _virtù_ of Maestro Giuliano and the desirability of keeping him in Siena, deliberated to accord to him a loan he requested, of seventy florins to buy a house."[230] Again, on May 25, 1421, the Republic of Siena wrote to Filippo Visconti Duke of Milan that a Maestro Giovanni, son of Maestro Leone da Piazza near Como, was anxious to return to his native country, to see his family and to arrange a law-suit; and they recommended him to the Lords of Milan because he had greatly won the affection and esteem of the Sienese republic by his good life and his eminence in his art of sculpture. A certain "Maestro Alberto di Martino de Cumo in provincie Lombardie" was engaged by the _Opera_ on March 2, 1448, as a builder, in company with Giovan Francesco of Valmaggia and Lanzilotto di Niccola of Como. When the Piccolomini wanted to build a splendid palace in Siena, they did not choose their architects from the faction of their townspeople, but from the original Lombard branch. Martino di Giorgio da Varenna (near Bidagio on Lake Como) was chief architect, and Lorenzo from Mariano in the Lugano valley assisted him as sculptor. He carved the beautiful capitals and friezes in the palace, and his work so pleased the Piccolomini, that they employed him to erect an altar and decorate their chapel in the church of S. Francesco. Milanesi says that Lorenzo da Mariano was one of the best artists of his time for foliaged scrolls and grotesques.[231] In 1506 he was _capo maestro_ of the Duomo of Siena. Maestro Lorenzo was no doubt one of the precursors of the sculptors of the beautiful cathedral of Como, and the richly ornate Certosa of Pavia, who were trained in the Sienese _laborerium_. A fellow-countryman, named Maestro Matteo di Jacopo, came from Lugano with Lorenzo, and together with Maestro Adamo da Sanvito (also in Val di Lugano) undertook the great engineering work of making an artificial lake, to drain the then malarious country round Massa in Maremma. Martino di Giorgio had a relative who became more famous than himself. This was Francesco di Giorgio di Martino--three names in rotation are generally enough to supply an Italian family for centuries,--who continued the work at Palazzo Piccolomini (Vasari gives him the credit for the whole), and was one of the architects of the palace at Urbino.