Bossòst, one of the most dynamic and colourful villages of the Baish (Lower) Aran, houses a magnificent example of Aranese Romanesque architecture: the church of Was Mair de Diu dera Purificacion. It stands near the boulevard which crosses the village, facing the old neighbourhood of El Cap dera Vila.
What is immediately striking about its magnificent architecture is its stylistic unity, which makes it a faithful visual documentation of Romanesque architecture as it evolved in the 12th century. Was Mair de Diu dera Purificacion is a compendium of the main attributes of the artistic legacy of the Romanesque style, with its three-nave basilical ground plan, built within a barrel vault and resting on circular pillars: its three apses, profusely decorated with sculptural elements of Lombard origin, its belfry, attached to the north-east angle with its decorative columns, bell-shaped and geminated windows and Lombardy arcatures and its two facades, each with a tympanum, of major iconographic and structural wealth, set on a series of decreasing arches.

Inside the church, the structural design of the Romanesque architecture of Was Mair de Diu dera Purificacion, is immediately apparent, with four arches separating the naves and the supporting circular pillars, all of which are made of finely-worked and squared stone and crowned by smooth imposts. One detail not to be overlooked is a fragment of mural in the central apse, which represents part of an Epiphany scene; these paintings date back to the end of the 13th century and to the beginning of the 14th.