This is from a DeI campaign I did a few years ago, as Arche Bosphorus(or, at this point, the Hellenic Confederation, as I confederated mainland Greece soon after I had dealt with the Scythians and Caucasians). If I remember correctyly my conquests were Eastern Scythia(absolute AIDS to fight in btw, no supply and all armies are horse archer cancer), the Caucasus, Dacia and Thrace, and then Persia. Persia at the time was held mostly by bloobed up Satraps and the Mauryans, both of which I destroyed, and acquired Elephants for my armies. Through all of this I had maintained a good relationship with Rome, with all manner of positive events, greatest of which was the acquisition of Pella. This began to swiftly change once we ran out of conquests in opposite directions, This resulted in a joint declaration of war by them and Boii, wheras i was joined by my Anatolian allies and Egypt. My armies were very out of position at the start of the war, but luckily either the AI was being indolent, or was in a similar situation, so I managed not to get driven into the Black Sea by the time their armies started showing. The war wasn't going well for the Ptolemy's however. Also, due to the Terrestrial nature of my conquests and the security of the Black Sea, my navy was rather laughable, and I wasn't able to contest the Adriatic against them, and thus my offensive grind to a halt while I built my fleet. This allowed multiple Roman invasions of Epirus and Illyria across the sea and tied, and, in the Epirote case, destroyed, multiple of my armies. The Boii to the north made an advance Through the Alps unappealing and difficult, and I couldn't commit enough armies for a full on offensive against them. Eventually though I built up my fleet, beat up enough romans to manage an invasion into Brundisium.