In the 1750s, Jesuit priest Father Gabriel enters the eastern Paraguayan jungle to convert the Guaraní to Christianity.

Captain Rodrigo Mendoza is a mercenary and slave trader, and a guest of the Spanish governor, Don Cabeza.

Their heroic defense is quickly overcome by the superior weaponry and numbers of the enemy, and Mendoza is killed along with his men.

The soldiers encounter the Jesuits of the mission leading the Guaraní women and children singing in a religious procession.

The colonial forces organize a firing line and discharge their guns directly into the procession, killing the priests.

Most of the natives are subsequently captured to be sold as slaves, but a small group of children manage to escape into the jungle.

Days later, a canoe carrying the surviving children returns to the now pillaged and burned mission, retrieving their belongings.

A final title declares that many priests have continued to fight for the rights of indigenous people into the present day.

The Mission is based on events surrounding the Treaty of Madrid in 1750, in which Spain ceded part of Jesuit Paraguay to Portugal.

He oversaw the transfer of seven missions south and east of the Río Uruguay, that had been settled by Guaraní and Jesuits in the 17th century.

[6] Father Gabriel's character is loosely based on the life of Paraguayan saint and Jesuit Roque González de Santa Cruz.

[7] The waterfall setting of the film suggests the combination of these events with the story of older missions, founded between 1610 and 1630 on the Paranapanema River above the Guaíra Falls, from which Paulista slave raids forced Guaraní and Jesuits to flee in 1631.

[6] The historical Altamirano was not a cardinal sent by the Pope, but an emissary sent by the Superior General of the Society of Jesus, Ignacio Visconti, to preserve the Jesuits in Europe in the face of attacks in Spain and Portugal.

The film asserts that the Guaraní accepted Christianity immediately, although in reality native religious beliefs persisted for several generations.

[9] The movie also portrays the Jesuits engaged in armed resistance to Spanish attempts to force the missions to relocate in the 1750s.

In reality, the revolt was carried out by the Guaraní after the Jesuits had turned over control of the missions to the colonial governments of Spain and Portugal.

The tunnels of Fort Amherst in Kent were used as part of the monastery where Mendoza (Robert De Niro) sequesters himself after murdering his brother.

The site's critics consensus reads, "The Mission is a well-meaning epic given delicate heft by its sumptuous visuals and a standout score by Ennio Morricone, but its staid presentation never stirs an emotional investment in its characters.