The church of San Esteban in Villanua is of Romanesque origin although it underwent substantial modifications in later building stages. All that remains of the early period is a wall, with corbels along its upper edge, where the original doorway used to be. The church was completely refurbished in the 18th century and its present appearance dates from that period. It is made up of a large main nave and another lateral nave separated by a column which supports elliptical arches.

On the north side there are two rectangular chapels which almost make up a third nave due to their size. On the south side there is a small portico which shelters the doorway into the church. The artistic collection within the temple is varied and of great value. The main altarpiece, dedicated to St Stephen, is a sculpture dating from the 17th century which follows the creative criteria of the Romanist sculpture workshops of Sangüesa. It has three levels – bench, main level in three sections and penthouse.

The oldest figure kept in this church is a Romanesque carving of Nuestra Señora de los Ángeles, from the now derelict chapel of the same name. Dated between the end of the 11th and beginning of the 12th century, it represents the Virgin as the Throne of Knowledge and conserves the original polychrome finish.

Also of great interest is the simple altarpiece of the Holy Christ which houses a magnificent carving of Christ Crucified. The church contains other Barroque pieces of interest, such as the altarpiece of St Orosia which has a skilled painting of her martyrdom. The canvas of the 17th-century altarpiece of the Immaculate Conception is of even greater quality. Lastly, an 18th-century altarpiece of the Virgin of the Pillar decorates the eastern wall of the lateral nave.