Complex sentence: At the start of World War I "Körös" was based at Zemun, just upstream from Belgrade on the Danube, under the command of "Linienschiffsleutnant" (LSL) Josef Meusburger., accompanied by another three monitors and three patrol boats.
Split into simpler sentences: At the start of World War I, "Körös" was based at Zemun, just upstream from Belgrade on the Danube. Her commander was "Linienschiffsleutnant" (LSL) Josef Meusburger, and she was accompanied by another three monitors and three patrol boats.