Sebastião de Arriaga

Sebastião José de Arriaga Brum da Silveira (1774–1826) was a Portuguese military commander.

Early career Arriaga enlisted at the age of nineteen as an ensign in the Infantry company of Fortaleza de Santa Cruz, Faial Island, in The Azores, later transferring to Artillery. The following September–October, his company was one of the two Portuguese Artillery companies that formed part of Hill's forces, together with Lefebure's RHA Troop, Hawker's and Meadows's Royal Artillery Companies. for making "good and accurate fire" and averaging fifteen shots per gun.

Arriaga's 1st Brigade took part in the Siege of San Sebastián (7 July – 8 September 1813) as part of Dickson's siege artillery, and was again mentioned in dispatches by Dickson.

Family Arriaga was the grandfather of Manuel de Arriaga, the first elected president of the First Portuguese Republic.