Alexander died on June 10, 323 BCE. Atropates' new son-in-law Perdiccas was named regent of Alexander's half-brother Philip III. After the "Partition of Babylon" in 323 BCE, Media was divided into two parts. The greater portion in the south-east was governed by Peithon, a general of Perdiccas. The smaller portion in the north west was given to Atropates. At some point, Atropates made his part of Media an independent kingdom. His son-in-law Perdiccas was murdered by Peithon in the summer of 320 BCE.