By November 1265, Harvey IV first leased the customs of the Abbey of Saint-Mathieu for the next seven years for a fee of 3,000 livres.
In 1273, he started selling different small fiefs, before selling definitively the port of Saint-Mathieu and its customs to Peter of Brittany on behalf of his father Duke John I for a fee of 16,000 livres in August 1275.
Harvey IV had already sold him on 17 February 1274 the town and castle of Le Conquet for a fee of 1,500 livres, Plouarzel and Plougonvelin for a fee of 4,000 livres the same year, Saint-Renan, the castle of Damani and all his remaining properties in the three Bishoprics of Léon, Tréguier and Cornouaille, that is to say the remaining of his estate, on 26 October 1276 for a fee of 7,210 livres.
[4] This charter was confirmed the same month by Harvey's sister Amé of Léon and her husband Rolland of Dinan-Montafilant.
[a] They had a daughter, Anné of Léon who married Prigent de Coëtmen, Viscount of Tonquédec before 1298.