[2] He had kinship with the Aragonese queen consort Maria de Luna and the anti-pope Benedict XIII.
When Martin I died, he supported James II of Urgell in his unsuccessful candidacy to the throne.
In 1411, he and a gang of men murdered the Archbishop of Zaragoza, García Fernández de Heredia, an ally of the child candidate Louis of Anjou.
De Luna accepted the decision, but later rebelled along with the count of Urgell.
The rebellion was defeated and Antón de Luna was dispossessed of his properties and arrested in Mequinenza.