Caesar claimed that, in the course of his conquest of Gaul, the Britons had supported the campaigns of the mainland Gauls against him, with fugitives from among the Gallic Belgae fleeing to Belgic settlements in Britain, and the Veneti of Armorica, who controlled seaborne trade to the island, calling in aid from their British allies to fight for them against Caesar in 56 BC. Strabo says that the Venetic rebellion in 56 BC had been intended to prevent Caesar from travelling to Britain and disrupting their commercial activity, suggesting that the possibility of a British expedition had already been considered by then.