The objectives of the brief campaign soon to be considered were Sarajevo, the capital of Bosnia, and Ragusa, the famous little seaport on the Adriatic. Ragusa is of especial interest on account of its remarkable history. In the Middle Ages it was the most important seaport in that part of the world. Its ships sailed over all the Mediterranean and from them is derived the word "argosy," signifying a ship laden with wealth. Again and again the Turks attempted to conquer this little state, which was at that time a republic, but always the Ragusans beat off the enemy. For the country about is so rocky, so rough, that the city was easily defended, especially in that time when nearly all fighting was hand to hand. The first and foremost word in the Great War--the key word--is Sarajevo. Here is the scene of the assassination of the Crown Prince of Austria, which was at least the final cause of the war. As we enter it we find a population of about forty thousand, half of which are Mohammedans. It is a large, straggling town, situated in a narrowing valley overtopped by steep hills on either side, which close in a narrow gorge in the east and broaden into a plain on the west. It was to the eastward, however, that we shall find the heavy fighting along the Austro-Serbian frontier. The armies along the Danube will soon command our attention. As they follow the river toward Belgrade, the capital of Serbia, it is no longer the "Blue Danube" of the famous German song. Here, in fact, it is a broad, mud-colored river, dotted with a number of low islands along its center. Belgrade, where the first shots of the war were fired, is located on rather high ground, backed by a semicircle of low hills in its rear. But opposite all is flat and, in places, marshy. Modern guns could, of course, keep up an effective fire across the river at this point, as in fact they did before the actual invasion of Serbia began, but the conditions for a crossing are not favorable. It was from the west, from the Bosnian side, that the actual attack was made. Just below Belgrade the river Save, shallower and narrower, empties into the Danube, forming the frontier westward, past Shabatz, to Ratcha, where the Drina, flowing down from the Macedonian highlands northward, joins it, forming the western frontier between Bosnia and Serbia. The Drina, where much fighting occurs, is no ordinary waterway, no mere mountain stream, though it lies in a mountainous country. Before reaching its junction with the Save it is fed by many important tributaries. Ever swift, often torrential, it has washed out a bed of imposing width, and by a constant cutting out of new courses has created a series of deltas. It was one of the largest of these islands, that of Kuriachista, between Losnitza and Leschnitza, that the Austrians chose as a base for their first invasion. From this point up and around to Shabatz lies the bloody field of the Austro-Serbian battles.