“...San Tommaso became soon the first basin, the Darsina, where the galleys were built, and later launched, under covered arches which can still be seen...” from 'E. and F. Poleggi (edited by), “Description of the City of Genoa in 1818 from an anonymous” Genoa 1974.
Arsenale and Darsena area in Genoa, as it is easy to imagine, had very ancient origins. The first natural dock of the port, the Mandraccio, was initially used to repair damaged boats because it was a sheltered and peaceful place. However, in 1200, a new suitable basin was built to repair and construct  boats.
The arsenal was built later and was completed only in the fifteenth century.
In 1300 Genoa was equipped with two basins: the one in the east served the ships transporting goods and wine (Darsena del vino), while the west one was used for shelter and construction of the galleys, the warships (Darsena della Galee) .
In 1851, Carlo Alberto decided to build in the eastern part of the Darsena, the first dry dock.