Portugal has long had a special relationship with the Knights Templar, a group of Medieval knights brought to recent attention by Dan Brown's book, The Da Vinci Code. When the Pope Clement V disbanded the order in 1307 and turned their lands and castles over the kings of each country (some of whom has pressured the Pope to destroy the powerful group), King Dinis of Portugal did not join his fellow monarchs in seizing the Templars’ rich treasuries.
He had not forgotten that only a few years earlier these knights had helped him rid Portugal of the Islamic caliphate that had ruled it for centuries. While he disbanded them officially, as the Pope had directed, King Dinis petitioned the Pope to form a new Order of Christ.
The Pope agreed, and King Dinis promply let it be known that any Templar was welcome, and he immediately turned over all their castles to the new order. The Templar’s richest and most elaborate headquarters had been at Tomar, but to install the new order there would have brought too much attention to the connection. So instead he made the less conspicuous castle at Castro Marim, in the Algarve their command -- not a bad location, since it overlooked the Guardiana River that divides Portugal from its traditional rival, Spain.
Both Portuguese castles still stand, and several sites in Spain are connected with the order. Below the Alcazar in Segovia, in the valley of Eresma, is the Templar church of La Vera Cruz. The castles in Ponferrada (in Leon) and Barberà are connected to the order, and in Vigo the Knights Templar are reputed to have planted an olive tree at the cathedral in the 14th century, which became the city’s symbol. In the Paseo de Alfonso a tree still grows that is believed by locals to have sprung from a cutting of the Templars’ original tree.