Its full name is the Ancient, Most Noble and Enlightened Military Order of Saint James of the Sword, of the Scientific, Literary and Artistic Merit (Portuguese: Antiga, Nobilíssima e Esclarecida Ordem Militar de Sant'Iago da Espada, do Mérito Científico, Literário e Artístico).

In 1170, Ferdinand II granted the new order the castles of Cáceres and Monfragüe, which had been confiscated from Gerald the Fearless in 1169, and would make further donations thereafter.

In January 1174, Alfonso VIII granted them the citadel of Uclés, which would later serve as the headquarters of the Order of Santiago as a whole after the reunification of the León and Castile in 1230.

[4] In 1186, after the death of Afonso I, King Sancho I of Portugal donated to the Order of Santiago the Portuguese dominions of Palmela, Almada and Alcácer do Sal, all in the Setúbal District, south of Lisbon), thus marking their return.

In 1249, Paio Peres Correia and the Order of Santiago helped Afonso III of Portugal sweep up the final Moorish possessions in the Algarve.

[6] The mastership of the three major orders – St. James, Christ and Aviz – would remain in the hands of princes of the royal family (infantes) for much of the next century.

But Diogo died within a year, so Peter passed the mastership on to his nephew, Infante Ferdinand, Duke of Beja, the younger brother of King Afonso V of Portugal.

[7] In the 1452 bull Ex apostolice sedis, Pope Nicholas V confirmed once more Ferdinand's appointment and put a definitive end to questions (up to then still being raised by Castile) about the autonomy of the Portuguese branch of Santiago.

[7] At Infante Ferdinand's death in 1470, all his titles, including both the orders of Christ and Santiago, were inherited by his eldest son, João, Duke of Viseu.

As A result, the Order of St. James supplied a greater share of the knights for the slate of new expeditions organized by John II in the 1480s.

As a result, John II launched a campaign to legitimize his natural son, Jorge de Lencastre, as royal heir.

The Order of Santiago played a leading role in the early India expeditions, a legacy project from the reign of John II.

But chronicler Gaspar Correia (p. 15) reports that as soon as the ships left sight of Lisbon harbor, Paulo da Gama pulled 'the royal standard' down from the mast.

In January, 1505, Manuel managed to coax D. Francisco de Almeida to abandon Santiago and move over to the Order of Christ.

This was followed by a second bull, Praeclara carissimi, issued by the pope under great diplomatic pressure by John III in December 1551, appointing the Kings of Portugal as masters in perpetuity of all three military orders (Christ, Santiago and Aviz), thus bringing an end to the independence of the military orders in Portugal.

The Order of Santiago possessed many domains granted by the Portuguese Crown, almost all of them south of the Tagus river, clustered in the Sado region and lower Alentejo.

As the most southerly of the four Portuguese military orders, the Santiago knights were the first frontline against incursions from the Moorish Algarve in the 13th century.

These domains were partitioned into comendas, and granted by the Order in commendam to a Santiago knight (comendador) entrusted with the obligation of defending them.

The grand masters of the Order were among the most powerful men in Portugal, and comendadors stood at the peak of rural society in their districts.

[10] By the 15th century the large comendas of the Order of Santiago were (from north to south): Arruda and Santos (both north of the river), then Palmela, Setúbal, Sesimbra, Cabrela, Alcácer do Sal, Torrão, Grândola, Ferreira, Santiago do Cacém, Sines, Aljustrel, Messejana, Casével, Garvão, Castro Verde, Mértola, Almodôvar, and (on the southeast Algarve coast) Cacela.