Already in the year 1527, after the expulsion of the Medici, a subordinate board had been created, to whom very considerable executive and administrative faculties were delegated.

This board, called the Nove della Milizia, or the Nine, were empowered to enrol all the burghers under arms, and to take charge of the walls, towers, bastions, and other fortifications.

It was also within their competence to cause the destruction of buildings, and to compensate the evicted proprietors at a valuation which they fixed themselves.

In the spring of 1529 the War Office decided to gain the services of Michelangelo, not only because he was the most eminent architect of his age in Florence, but also because the Buonarroti family had always been adherents of the Medicean party, and the Ten judged that his appointment to a place on the Nove di Milizia would be popular with the democracy.

The patent conferring this office upon him, together with full authority over the work of fortification, was issued on the 6th of April.