Complex sentence: However, the archduke defeated the French troops at the 1479 Battle of Guinegate, and when Mary died in 1482 Maximilian retained Flanders according to the 1482 Treaty of Arras.
Split into simpler sentences: However, the archduke defeated the French troops in 1479 at the Battle of Guinegate. When Mary died in 1482, Maximilian retained Flanders according to the terms of the 1482 Treaty of Arras.