Round Church (Charola)
"The Romanesque round church is a Roman Catholic Church from the castle (charola, rotunda) was built in the second half of the 12th century by the Knights Templar. From the outside, the church is a 16-side polygonal structure, with strong buttresses, round windows and a bell-tower. Inside, the round church has a central, octagonal structure, connected by arches to a surround
ing gallery (ambulatory). The general shape of the church is modelled after similar round structures in Jerusalem: the Mosque of Omar and the Church of the Holy Sepulchre."
~ Convent of the Order of Christ
"The Convent of the Order of Christ ("Convento de Cristo") is originally a Templar stronghold built in the 12th century. After the Order of the Knights Templar was dissolved in the 14th century, the Portuguese branch of the order was turned into the Knights of the Order of Christ, which supported Portugal's maritime discoveries of the 15th century."
IN: en.wikipedia.org/wiki/Convent_of_the_Order_of_Christ
Convento de Cristo, Tomar (UNESCO site):
www.conventocristo.pt/en/