Emperor Diocletian made history in 305 AD by being the first Roman ruler to give up his throne voluntarily

Yes, Roman Emperor Diocletian famously retired in 305 AD to his palace on the Dalmatian coast (modern-day Split, Croatia) and spent his remaining years gardening, with a particular fondness for growing cabbages. When urged to return to power to resolve political chaos, he famously refused, stating that if others could see the vegetables he grew with his own hands, they would not ask him to return.