The Battle of Baron is the first armed engagement in Final Fantasy IV: The After Years, in the chapter Prologue: Return of the Moon. It ends in a decisive victory for the Creator and his Maenads, being the first known defeat suffered by the world's strongest military power.
Arriving with the True Moon, the Creator—regarding the evolution of humans a failure—sets to collect the Crystals of the Earth. His servants, the Maenads, have already attacked the Red Moon and the Lunarians, unaware that the latter had placed half of the Crystals on Earth. They travel to Earth on a meteor and set off to capture the Crystals from the various kingdoms holding them; Baron, Mysidia, Troia, Damcyan and the dwarves. Possibly due to its status as the world's strongest military power, Baron becomes the first target.
The attack on Baron starts with an assault on the Red Wings, including a ship commanded by Biggs and Wedge and with Prince Ceodore among its crew. Despite putting up tough resistance, the ship is overwhelmed and crashes, killing everyone except Ceodore.
Baron Castle comes under attack, and King Cecil Harvey rushes into action alongside his army. Initially surprised that monsters made it past the castle's walls, he learns they infiltrated the castle from the air. The Baron Army suffers immense casualties defending the castle, and in the end Cecil orders his wife Queen Rosa and his friend Cid Pollendina to evacuate without him. He witnesses the arrival of Bahamut and a "Mysterious Girl," who to his surprise knows his name. Cecil is attacked by Bahamut, a fight he is bound to lose; afterwards the Maenads take control of Cecil's mind, seeing him as potentially useful in their quest for capturing the Crystals.
To preserve Cecil's credibility the Maenads make it appear like Cecil repelled the assault. Citizens commend their king for "fending off" the attack without endangering civilians, but Ceodore becomes suspicious when castle guards refuse to let him in. The Maenads would use Cecil and the Red Wings to attack other nations to steal their Crystals, repeating history.