 According to the act of infeudation, "not included, but absolutely excluded, and expressly excluded [are] the Sienese fortresses, castles, ports, places and farmland of, namely, Porto Ercole, Orbetello, Talamone, Monte Argentario and Porto Santo Stefano", a territory of about 287 km2.In April 1558, the French, who still held Talamone, made an unsuccessful assault on Orbetello and in September of the same year, the Spaniards took Talamone by force.Control of the "Presidi" allowed the Spanish to monitor maritime traffic between Genoa and Naples, since in the 16th century ships kept close to the coast.