Complex sentence: In 605, they staged a large scale raid southward, invading Sui territories (Northern modern Shanxi, Hebei), they were eventually crushed by a Sui General leading 20,000 Turkish cavalry.
Split into simpler sentences: In 605, they staged a large scale raid southward, invading Sui territories (Northern modern Shanxi, Hebei),. They were eventually crushed by a Sui general leading 20,000 Turkish cavalry.