Forte de Santo Amaro

Forte de Santo Amaro, also called Forte do Areeiro, Fort of Santo Amaro do Areeiro or simply the Forte Velho ("Old Fort"), is a seventeenth-century fortress in the municipality of Oeiras, in the Lisbon District of Portugal. It stands on the right bank of the River Tagus, west of the capital, and belongs to the historic defensive system that guarded the mouth of the river.

Why was a fort built at Oeiras?

The fort dates from the Portuguese Restoration War (1640-1668) and was ordered by King John IV. Its job was to reinforce the defence of the Tagus estuary, which was already covered by the nearby Fort of São Julião da Barra and the Fort of São Lourenço do Bugio, built on a shoal in the middle of the river mouth. Whoever controlled the entrance to the estuary controlled the sea route to Lisbon, so defences were added here one after another.

When was it built, and by whom?

Construction began in 1647 under the direction of António Luís de Meneses and was completed in 1659. The work therefore took more than a decade and ran alongside the war itself. The fort has a polygonal plan and a Mannerist design, typical of Portuguese military architecture of the period.

What happened to it later?

By 1735 the fort was reported to be in poor condition, and among other things its main door needed replacing. In 1751 further work was judged urgent. During the Spanish-Portuguese War of 1762-1763 it was garrisoned and armed with seven working cannon.

The fort also has a place in more recent history. After the coup of 25 April 1974, known as the Carnation Revolution, the Prime Minister of Portugal lived here. Over the years it has undergone several restorations, yet it has kept its original layout. The one noticeable departure from the original design is the cement wall on the exterior.

What to know before you go

• Location: Oeiras, right bank of the Tagus, at roughly 38.681 N, 9.315 W.
• Type of site: a coastal fort from the mid-seventeenth century, part of the river-mouth defences together with São Julião da Barra and Bugio.
• Style: Mannerist, polygonal plan.
• Combine it with other sites: if you are interested in how Lisbon was defended, plan a route linking several forts and compare how they sit along the coast.

Check current access and opening arrangements before you travel, since the fort may be used for purposes other than a museum and visiting rules can change.

Frequently asked questions

Is Forte de Santo Amaro the same as Forte do Areeiro? Yes. The fort is known by several names: Santo Amaro, Areeiro, Santo Amaro do Areeiro and Forte Velho.

When was the fort built? Construction ran from 1647 to 1659, during the Portuguese Restoration War.

Who commissioned it? King John IV ordered it, and António Luís de Meneses directed the work.

Why is it significant? Together with the forts of São Julião da Barra and Bugio, it protected the approach to Lisbon from the Tagus.

Has the fort changed over the centuries? It has been restored several times but has kept its original plan. A more recent addition is the cement wall on the outside.

Did anyone notable live there? After 1974 it was the residence of the Prime Minister of Portugal.