Turn 237: Be proactive and declare war on Harald yourself. If you want to, you can also bribe him to attack your friend Genghis beforehand, then declare war and get your resources back. I'd say this is cheesy and unnecessary on Prince, but it's a useful tactic to remember for Deity though.
Unit movements: Send pikeman and bow from Akkad to Babylon. Swordsman hits the wounded Catapult, then you finish it off with the bowman from Babylon. Other bowman moves onto the road.
Turn 238: Harald moves in. Akkadian bowman takes a shot at a spearman, Pikeman stands in front of it as a blocker unit. Swordsman hits the Catapult, bowmen finish it off.
(sry about the text blocking the units - that's a swordsman on the wheat and a bowman east of it)
Turn 239: Retreating already? We chase him out. Swordsman moves onto the Furs to give Pikeman a flanking bonus, Pikeman hits the plains Spearman, Bowmen move along the road and finish it off. Third bowman moves onto the forest hill NE of the Furs to box in the other Danish Spearman.
Turn 240: Swordsman moves into Babylon to heal, Pikeman also moves onto friendly territory to heal. Two Bowmen shoot the retreating Spear. Note I moved one of them to the plains tile and it says he has 0/2 moves; he actually has 0.5 because moving along roads is cheaper, and half a move is still enough to shoot (I believe the Enhanced User Interface actually displays the fraction moves correctly). I did this was to keep the Furs spot open for the third Bowman, in case the Spearman survived the first 2 shots. He didn't, so I just move the bowman closer to Babylon, across the river.
Turn 241: Harald's attack seems to be over... I see nothing. I move another bowmen across the river in case Harald's coming from the east.
Turn 242: A spearman. We've been pretty good at killing these so far. I move the bowmen in position to shoot him twice next turn if he moves onto the jungle tile.
Turn 243: He retreats instead so I just take a shot with one bowmen and fortify all other units.
Harald sues for peace in the turn rollover.