Thus the invaders seemed to have gained a secure base on the Danube, from Sistova to Nicopolis, whence they could safely push forward their vanguard to the Balkans. In point of fact their light troops had already seized one of its more difficult passes--an exploit that will always recall the name of that dashing leader, General Gurko. The plan now to be described was his conception; it was approved by the Grand Duke Nicholas. Setting out from Sistova and drawing part of his column from the forces at Biela, Gurko first occupied the important town of Tirnova, the small Turkish garrison making a very poor attempt to defend the old Bulgarian capital (July 7). The liberators there received an overwhelming ovation, and gained many recruits for the "Bulgarian Legion." Pushing ahead, the Cossacks and Dragoons seized large supplies of provisions stored by the Turks, and gained valuable news respecting the defences of the passes. The Shipka Pass, due south of Tirnova, was now strongly held, and Turkish troops were hurrying towards the two passes north of Slievno, some fifty miles farther east. Even so they had not enough men at hand to defend all the passes of the mountain chain that formed their chief line of defence. They left one of them practically undefended; this was the Khainkoi Pass, having an elevation of 3700 feet above the sea. A Russian diplomatist, Prince Tserteleff, who was charged to collect information about the passes, found that the Khainkoi enjoyed an evil reputation. "Ill luck awaits him who crosses the Khainkoi Pass," so ran the local proverb. He therefore determined to try it; by dint of questioning the friendly Bulgarian peasantry he found one man who had been through it once, and that was two years before with an ox-cart. Where an ox-cart could go, a light mountain gun could go. Accordingly, the Prince and General Rauch went with 200 Cossacks to explore the pass, set the men to work at the worst places, and, thanks to the secrecy observed by the peasantry, soon made the path to the summit practicable for cavalry and light guns. The Prince disguised himself as a Bulgarian shepherd to examine the southern outlet; and, on his bringing a favourable report, 11,000 men of Gurko's command began to thread the intricacies of the defile.