Victor Cordonnier, chosen by Sarrail from Joffre's shortlist of three, arrived at Salonika on 11 August to command the French contingent. But the Bulgars struck first on 17 August, reinforced by two German divisions brought from the Vosges to the River Vardar. With Bulgarian morale crumbling, further German battalions were brought from Champagne, Poland and the Vosges, as well as some heavy guns from Verdun. The Bulgars began a major offensive against Sarrail's right and left – initially successful on the latter. Sarrail's forces held off the offensive with difficulty by 28 August and Sarrail recast his plans to avoid attacking the Germans on the Vardar.