Complex sentence: Around 1287 or 1288 Milutin helped his brother Stefan Dragutin to pacify two Bulgarian nobles in today's north-east Serbia, in the Branicevo region, but those nobles were vassals of the Bulgarian prince of Vidin Shishman who sought revenge.
Split into simpler sentences: Around 1287 or 1288 Milutin helped his brother Stefan Dragutin to pacify two Bulgarian nobles in today's north-east Serbia, in Branicevo region. But those nobles were vassals of Bulgarian prince of Vidin Shishman who sought revenge.