Soon after the city was founded in 1565, the Portuguese began building defenses to protect against sea attacks. One of the earliest batteries – Our Lady of the Guide – was positioned on a promontory at the eastern mouth of Guanabara Bay. This evolved into Santa Cruz da Barra Fortress around 1614. By the end of the 17th century, the port was exporting considerable gold and diamonds. This made Rio an attractive target for French privateers. The fort successfully thwarted an attack by Jean-François Duclerc in 1710 yet failed to repel a similar afront by René Duguay-Trouin the following year. The fort’s complex and firepower was expanded considerably during the 18th century. During the Revolt of the Armada, Fortaleza de Santa Cruz da Barra engaged in its last two battles in 1893 and 1894. Since an extensive restoration, Fortress of Santa Cruz opened for tourism. It is also the Artillery Division for the 1st Army Division.