Saint Pompeia (in Latin: Alma Pompeia or in Breton: Koupaia [1]), also known as Aspasia, is a legendary Breton saint who supposedly lived in the 6th century.

According to the life of her son, Tudwal, Pompeia was the sister of King Riwal II of Domnonée.

[2] Tradition at Langoat further asserts that she became one of the wives of the King Hoel Mawr (or the Great) of Cournaille and Over-King Brittany.

[3] After being exiled in Britain for some years, Pompeia eventually returned to her husband's kingdom with her daughter, Saint Scaeva, and her son, Saint Tudwal.

[2] She settled near the monastery of Tréguier, founded by the latter, and died where the church of Langoat stands today.