Suddenly, on August 12, 1914, there came a burst of rifle fire and the boom of heavy field guns, and a fleet of barges, under cover of this fire, emerged from around both ends of one of these islands and made for the Serbian shore. The two battalions of Third Reserve Serbians, stationed there as an outpost, trained their old De Bange field guns, of which they had two batteries, on the oncoming swarms and began firing. But the Austrian fire became heavier and heavier; a blast of steel pellets and shells swept through the cornfields and the plum orchards, tearing through the streets of the village and crumpling up the houses. The breastworks of the small Serbian detachment were literally the center of a continuous explosion of shells. When a full tenth of their number lay dead or disabled, the Serbians began retiring across the cornfields and up the slopes leading to the heights behind Losnitza. There, on higher ground, which offered more effective shelter, they made a determined stand and continued their fire on the Austrian masses. Having crossed the river, the Austrians threw up defensive breastworks and dug elaborate trenches, thus fortifying their crossing. Next they built a pontoon bridge, and then the main Austrian army poured across; a whole army corps and two divisions of a second. Meanwhile, on the same day, August 12, 1914, a similar event was happening at Shabatz, on the Save, where that river takes a sharp southward turn and then swings up again before joining the Danube at Belgrade. Here the country is a level plain, really the southern limit of the great plain which stretches up to the Danube, past Belgrade and so into Hungary. Here, too, the Austrians screened themselves behind an island in the river, then hurled their forces across, driving the feeble detachment of Third Reserve Serbian troops back across the plain up into the hills lying to the southeast of Shabatz. Then the advance guard of the Austrian Fourth Army occupied the town, strongly fortified it and built a pontoon bridge across the river from their railroad terminus at Klenak. Further passages of a similar nature were forced that day, August 12, 1914, at other points by smaller forces; one at Zvornik and another at Liubovia. In addition the Austrians also threw bridges across the river at Amajlia and Branjevo. Thus it will be seen that the invasion covered a front of considerably over a hundred miles and that six strong columns of the enemy had crossed, all of which naturally converged on Valievo. For Valievo was the terminus of a small, single track railroad which joined the main line at Mladenovatz. Thus the Austrians would have a convenient side door open into the heart of Serbia which was, of course, their main objective. To this Belgrade was merely incidental. With this line of transport and communication in Austrian hands, Belgrade would fall of itself.