by 1718, ilha das cobras counted twenty six guns and 716 bullets. in this time period the island was a crucial in the protection against raiders in the gold and diamond trade,  that made its way through the port of rio de janeiro - the fortaleza de são jose da ilha das cobras is the portuguese name for the old fortress located on cobra island in guanabara bay in rio de janeiro. this island was known for years as paranapecu or das madeiras. erected in 1624 by the recommendation of the then-governor, martim de sa (1623-32), this was the first defensive structure built on the island.

in 1639, another structure was added with the intention of defending the lower part of the island. by 1703, the newly elected governor d. alvaro da silve e albuquerque added a third structure, this time along the beach. all of these combined to form a cohesive and advanced wall of defense against potential threats.