Short answers, pulled from the story.
The Convent of Christ in Tomar was founded by the Knights Templar in 1118, with the construction of the circular oratory completed by Grand Master Gualdim Pais around 1160. Building and renovation continued through the 16th century, with the Cloister of John III finished in 1591.
The Castle and Convent of Christ in Tomar was listed as a UNESCO World Heritage site in 1983. It is recognised as a historic and cultural monument containing examples of Romanesque, Gothic, Manueline, and Renaissance architecture spanning several centuries.
The Romanesque round church at the Convent of Christ was modelled after the Dome of the Rock in Jerusalem, which the crusaders believed to be a remnant of the Temple of Solomon. The Church of the Holy Sepulchre in Jerusalem may also have served as a model.
When the Templar Order was dissolved, Pope John XXII established the Order of Christ on the 14th of March 1319 at the request of King Denis of Portugal. The Templar members, assets, and seat at Tomar were transferred to the new order, with the seat formally converted in 1357.
The Chapter House Window, also called the Janela do Capitulo, is a large window on the western facade of the Manueline nave, visible from the Saint Barbara Cloister. It is decorated with carved ropes, corals, vegetal motifs, and the emblems of the Order of Christ and King Manuel I, and is considered one of the masterworks of Manueline decoration.
Diogo da Gama, brother of the navigator Vasco da Gama, is buried in a Manueline tomb dating to around 1523 in the Claustro do Cemiterio at the Convent of Christ. The cloister was built under Henry the Navigator as a burial site for knights and monks of the Order of Christ.