During the winter of 58–57 BC rumours came to Caesar's ears that the Belgae tribes were forming a union because they feared possible Roman interference in their affairs. The union included the Bellovaci, Suessiones, Nervii, Atrebates, Ambiani, Morini, Menapii, Caleti, Veliocasses, Viromandui, Aduatuci, Condrusi, Eburones, Caeroesi, and Paemani tribes, and was under the leadership of Galba, a king of the Suessiones. These reports provided Caesar with a good pretext for conquering more than Gaul "itself", and for this, he raised two legions in Cisalpine Gaul (XIII and XIV) and convinced the Remi tribe to side with him.