Cassander (c.354-c.297 BCE) son of Antipater, from 318 the de facto ruler, and from 305 officially the king of Macedonia. He cleared his path to the throne by arranging the deaths, among others, of Alexander the Great's mother (Olympias), wife (Roxana) and her children. He married Alexander's half-sister (Thessalonica), for whom he established the Greek city which still bears her name. See here for a more detailed biographical sketch.