Complex sentence: For the Byzantines, the victory did not immediately lead to peace, however; in 1128, they were attacked by the Hungarians, and it was not until 1130 that they were able to finally secure their Danube frontier.
Split into simpler sentences: For the Byzantines, the victory did not immediately lead to peace, however. In 1128, the Byzantines were attacked by the Hungarians, and it was not until 1130 that they were able to finally secure their Danube frontier.