Carmen de expugnatione Salaciae

The Carmen de expugnatione Salaciae ('Song of the Conquest of Alcácer do Sal') is a Latin epic poem in 115 elegiac couplets describing the siege of Alcácer do Sal in 1217. It was written by Goswin of Bossut for Soeiro Viegas, bishop of Lisbon.

The Carmen is "the most detailed and full account to have survived for the definitive taking of Alcácer" from the Almohads by the Portuguese with help from the soldiers of the Fifth Crusade. In modern studies, it is usually grouped with two earlier accounts of northern crusaders' activities in Portugal, De expugnatione Lyxbonensi of 1147 and the De itinere navali of 1189.