The siege is broken
As things stand, the second chapter of this chronicle is beginning on a dark note. I'm behind in tech, being only the seventh of 12 civilizations to reach the Classical Era. My economy is bankrupt, which in Civ V, stunts your scientific progress. I really need to research the wheel so I can start building roads and benefiting from the pantheon bonus I worked so hard for. I set my tech path toward Currency, which will help my economy and pick up wheels on the way.
1000 B.C.: France fields a massive army to break the siege of Paris.
900 B.C.: The siege is finally broken when French forces from the south overwhelm some of the Celts' most experienced Pictish warriors. The Celtic general calls for a retreat, after 1000 years of occupying the surrounding forests and raiding the city outskirts. "Parisian" becomes a Celtic word for something very stubborn that is not worth fighting for.
This conclusion to a war that has eaten up a majority of my resources for dozens of turns is just shy of disastrous. I've lost one of my most experienced elite units (although they did withstand three attacks--while wounded, mind you--before succumbing.) And I have very little to show for it other than a small amount of Faith my Picts accrued dealing with French counter-attacks. Sacking Paris would have provided large gold bonuses to pad my flagging economy. But instead of going home rich, I'm forced to just go home, or risk losing more of my valuable units.
Later that year, the French and the Celts sign a peace treaty. The French try to parlay the new peace into a war on Russia. The Celts, who were abandoned by the Russians shortly into the war with France, find the offer tempting... but ultimately decline.
At this point, I'm in no position to turn around and start down the warpath again. Moscow is even further from my borders than Paris, and I did so much damage to the French military and infrastructure during the siege that it would almost be like fighting another war by myself. No, I'll go home and lick my wounds. The time has come to set my sights on my original target: London.