Just as France had reconstituted the Serbian Army (now based at Salonika) after her conquest in the winter of 1915-16, between January and June 1917 Berthelot supervised the reorganisation and retraining of the Romanian Army. The military mission was built up to almost 400 officers and 1,000 men. 74 75mm guns were sent (with another 102 "under consideration") and 120 old 120L heavy guns, but Britain was asked to supply howitzers. On the way home from his visit to St Petersburg in early 1917, shortly before the Fall of the Tsar, General de Castelnau stopped off for talks with Berthelot, and was told that the Romanian army could not be ready before 15 May. In August 1917 Foch sent General Albert Niessel (a Russian speaker and formerly commander of IX Corps), on a mission to Russia (by then a republic under the Provisional Government) in the hope of repeating Berthelot’s success there.