It's specifically the Roman UP, not a conqueror's event. And it's only once per civ.
What are your plans now? Personally I'd bargain for peace and return Shush. Or whatever it's called in Latin.
Then you can try nabbing the rest of N. Africa, France, Spain, and Britain.
Unless you aren't interested in the historic aspect anymore. In which case you should probably stop expanding for a bit and let your economy catch up.
I'm still aiming for a historic Roman Empire, but things are looking up. I have only one city left to conquer at the end of this update
Jeez, I thought Mandate Armies only worked on the first civ DoWed, not all of them. That's freaking scary.
Haha, in total it's 10 legions and 5 catapults

.
On with the update:
In Rome, the people were amazed at yet another monument to Rome's power. The Great Cothon helped exploit the ocean further, while looking magnificent. After it was built, the Romans built a temple to their Gods.
Across the Empire, Celtic and Babylonian rebels were put down. The natives needed to learn the lands belong to the Romans! The Persian war front was going well under the new General, but orders from the Emperor himself came to leave Persian lands. Peace was soon made. Parsa will not feel Rome's wrath, for now.
Skirmishes with more rebels went on after the war, but they were put down. Rome's generals also plan on soon taking a Persian stable. These horses were rumored to be especially strong. General de Bouillon vowed to return to Persia and claim these horses and the city of Parsa for Rome.
Rome decided instead of destroying Persia, Egypt could be a better conquest. War was declared, and Legions mobilized. They later met with the main army to lay siege to Egypt's cities, which were soon destroyed. Carthage was taken by Egyptian Chariot riders, regrettably.
Meanwhile in Rome, work began on a lighthouse so great, trade would never be the same again. Jade found around the iron deposits near Rome increased the revenue in the city. While the Emperor oversaw the construction of the colossal lighthouse, a strange man from the far east arrived. A scholar released a work detailing that the Chinese Empire was larger than Rome. The scholar disappeared mysteriously, but Rome was now even more focused at becoming a greater power.
In Egypt, two of the Egyptian cities were razed upon capture. Not a single unit was completely destroyed. Instead of attacking the Egyptian capital, Rome's army headed to retake Carthage.
Constantinopolis was becoming a second Rome, and started construction of a wall, one of the first Roman walls in existence. In Rome, a great priest started preaching. This improved the production and value of the city.
Roman relations with China improve as Rome signs open borders and teaches China about metal working. The Roman army reached and retook Carthage.
Rome then met the Ethiopian people, who were hostile to Egypt. The Ethiopians took the Egyptian Capital, the last Egyptian city. Thinking it won't lose momentum, Ethiopia declared war on Rome...
I'm back in business with a positive gold flow. Didn't expect to war with Ethiopia, at least not this soon lol. Will update later today.