During the 16th century several important urban projects were carried out. The most important public project of this period, however, was the construction of a new circuit of city walls, which still survive. Sporadic efforts had been made in the late 15th century to modernize the old walls, but the subsequent expansionist policies of Florence made it imperative to strengthen Lucca's defences. Advice and plans were sought from the most eminent fortifications experts, but no comprehensive plan was ever adopted and the construction work (1544-1650) was directed by a series of engineers, including Baldassare Lanci, Francesco Paciotto and Muzio Oddi. The new brick walls were fortified by orillion bastions with three gates, an internal stepped rampart (now planted with trees) and a moat beyond. On the north and south sides the new walls followed the medieval line; on the west they extended out to a point, and on the east they took in a large area of gardens and vegetable plots; they never had to sustain an enemy assault, however.