In 1203, John exempted the citizens and merchants of Bordeaux from the "Grande Coutume", which was the principal tax on their exports. In exchange, the regions of Bordeaux, Bayonne and Dax pledged support against the French Crown. The unblocked ports gave Gascon merchants open access to the English wine market for the first time. The following year, John granted the same exemptions to La Rochelle and Poitou.