Complex sentence: After Svatopluk was assassinated during the Battle of Głogów in 1109, Bořivoj's attempts to regain the Bohemian throne failed, as in the following fratricidal war his younger brother Vladislaus I prevailed, backed by King Henry V of Germany.
Split into simpler sentences: After Svatopluk was assassinated during the Battle of Głogów in 1109, Bořivoj's attempts to regain the Bohemian throne failed. In the following fratricidal war that followed the battle, Bořivoj's younger brother Vladislaus I prevailed, backed by King Henry V of Germany.