Diocletian's abdication exposed the Tetrarchy's succession problem

The Tetrarchy delivered unusual cooperation after the third-century crisis, and Diocletian's voluntary abdication was unprecedented in Roman imperial history. Its weakness was succession: the system lacked a durable rule for choosing the next Caesars. Bypassing Constantine and Maxentius in favor of Severus and Maximinus exposed patronage, family interest, and loyalty inside the supposedly merit-based arrangement. The short and violent careers that followed show how quickly a stable governing structure can unravel when authority transfers are not accepted.