The Holy Trinity Church has a cross shaped plan with a dome. It is composed of the nave, narthex (entrance area) and the altar alcove. In the church many Byzantine architecture features have been skilfully used such as the inner organization of the space and the decorative and illuminative systems. These features, together with the pyramidal shape, forms and proportions give the church a picturesque appearance. The Byzantine architectural elements in the church have been combined with western architectural elements belonging to the same period.
Inside the church are two columns with reused capitals (thought to have been taken from classical ruins in the city). An inscription inside the church contains the name of Andronicus Paleologus (Governor of the province of Berat from 1302 to 1326), indicating that the church must have been built during the 13th or 14th century with his financial support.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.