As regards the Ottoman army, an English officer in its service, Lieutenant W.V. Herbert, states that the artillery was very good, despite the poor supply of horses; that the infantry was very good; the regular cavalry mediocre, the irregular cavalry useless. He estimates the total forces in Europe and Asia at 700,000; but, as he admits that the battalions of 800 men rarely averaged more than 600, that total is clearly fallacious. An American authority believes that Turkey had not more than 250,000 men ready in Europe and that of these not more than 165,000 were north of the Balkans when the Russians advanced towards the Danube[130]. Von Lignitz credits the Turks with only 215,000 regular troops and 100,000 irregulars (Bashi Bazouks and Circassians) in the whole Empire; of these he assigns two-thirds to European Turkey[131]. [Footnote 130: _The Campaign in Bulgaria_, by F.V. Greene, pt. ii. ch. i.; W.V. Herbert, _The Defence of Plevna_, chaps, i.-ii.] [Footnote 131: _Aus drei Kriegen_, by Gen. von Lignitz, p. 99.] It seemed, then, that Russia had no very formidable task before her. Early in May seven army corps began to move towards that great river. They included 180 battalions of infantry, 200 squadrons of cavalry, and 800 guns--in all about 200,000 men. Their cannon were inferior to those of the Turks, but this seemed a small matter in view of the superior numbers which Russia seemed about to place in the field. The mobilisation of her huge army, however, went on slowly, and produced by no means the numbers that were officially reported. Our military attaché at the Russian headquarters, Colonel Wellesley, reported this fact to the British Government; and, on this being found out, incurred disagreeable slights from the Russian authorities[132]. [Footnote 132: _With the Russians in War and Peace_, by Colonel F.A. Wellesley (1905), ch. xvii.] Meanwhile Russia had secured the co-operation of Roumania by a convention signed on April 16, whereby the latter State granted a free passage through that Principality, and promised friendly treatment to the Muscovite troops. The Czar in return pledged himself to "maintain and defend the actual integrity of Roumania[133]." The sequel will show how this promise was fulfilled. For the present it seemed that the interests of the Principality were fully secured. Accordingly Prince Charles (elder brother of the Prince Leopold of Hohenzollern, whose candidature for the Crown of Spain made so much stir in 1870) took the further step of abrogating the suzerainty of the Sultan over Roumania (June 3). [Footnote 133: Hertslet, vol. iv. p. 2577.]