The Fortaleza de São João da Barra do Rio de Janeiro, popularly known as the Fortaleza de São João or Forte (de) São João (Fort of St. John), is a 16th-century star fort

Star fort

A star fort, or trace italienne, is a fortification in the style that evolved during the age of gunpowder, when cannon came to dominate the battlefield, and was first seen in the mid-15th century in Italy....

 in the present-day Urca

Urca

Urca is a traditional and wealthy residential neighborhood with nearly 7,000 inhabitants in Rio de Janeiro, Brazil. Although most of the neighborhood dates from the 1920s, parts of it are much older...

 neighborhood of Rio de Janeiro

Rio de Janeiro

Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...

, erected by Estácio de Sá

Estácio de Sá

Estácio de Sá was a Portuguese soldier and officer who came to Brazil on orders of the Portuguese crown to wage war on the French colonists commanded by Nicolas Durand de Villegaignon , who had established themselves in 1555 at the Guanabara Bay in Rio de Janeiro, in the episode which became known...

 to protect Guanabara Bay

Guanabara Bay

Guanabara Bay is an oceanic bay located in southeastern Brazil in the state of Rio de Janeiro. On its western shore lies the city of Rio de Janeiro, and on its eastern shore the cities of Niterói and São Gonçalo. Four other municipalities surround the bay's shores...

 from French invasion

France Antarctique

France Antarctique was a French colony south of the Equator, in Rio de Janeiro, Brazil, which existed between 1555 and 1567, and had control over the coast from Rio de Janeiro to Cabo Frio...

.

The original fort was built in 1565 under Sebastian of Portugal

Sebastian of Portugal

Sebastian "the Desired" was the 16th king of Portugal and the Algarves. He was the son of Prince John of Portugal and his wife, Joan of Spain...

. An expanded and improved structure was put into service in 1618, consisting of four batteries

Land battery

A land battery is a special type of gun emplacement or anti-shipping naval interdiction fortification used in coastal defense to protect areas such as anchorages, harbors, and rivers...

 (São José, São Martinho, São Teodósio, and São Diogo). Its armaments were greatly reduced, and not manned, during Brazil's Regency period, but Dom Pedro II ordered the fort completely renovated in 1872, and it was equipped with a complement of guns, bunkers, and batteries, including fifteen Whitworth

Joseph Whitworth

Sir Joseph Whitworth, 1st Baronet was an English engineer, entrepreneur, inventor and philanthropist. In 1841, he devised the British Standard Whitworth system, which created an accepted standard for screw threads...

 cannons. It was manned as a coastal artillery

Coastal artillery

Coastal artillery is the branch of armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications....

 installation until 1991.

In 1930, the Brazilian Army

Brazilian Army

The Brazilian Army is the land arm of the Brazilian Military. The Brazilian Army has fought in several international conflicts, mostly in South America and during the 19th century, such as the Brazilian War of Independence , Argentina-Brazil War , War of the Farrapos , Platine War , Uruguayan War ...

's Centro Militar de Educação Física (created in 1922) was transferred to the Fortaleza de São João. This establishment was renamed in 1933 and continues to be based at the Fortaleza de São João, together with the directorate to which it is subordinated, the , since the latter's creation in 2002.