The Battle of Lesalia Plains is the first major engagement in the War of the Lions, the titular conflict of Final Fantasy Tactics: The War of the Lions, fought between the two main belligerents, the Dukes Larg and Goltanna, over the Royal City of Lesalia, the capital city of Ivalice.
At the opening of the War of the Lions, Duke Goltanna, at the behest of Delita Heiral, attempted to seize the initiative by moving the knights of his Order of the Southern Sky into the Royal City of Lesalia, and crowned the young Princess Ovelia Queen of Ivalice. At the same time, he overthrew much of the existing establishment in the city, and banished the ruling Queen Louveria, who was allied with his rival Duke Larg, to Fort Besselat. In response, Larg crowned the toddler Prince Orinus King and marched on Lesalia with his counterpart Order of the Northern Sky in opposition.
Although very little is known of the battle itself, apart from the deployment, by both sides, of heavy cavalry in the form of Chocobo Knights, it is known that Goltanna and the Southern Sky were unable to hold the city, and instead retreated to their other strongholds at Fort Besselat and Zeltennia Castle. Henceforth, Lesalia became the wartime base of operations for Larg and the Northern Sky, though heavy fighting persisted in the region for some time, and the city itself was at times threatened by the famed Count Cidolfus Orlandeau, one of Goltanna's subordinate commanders, the so-called "Thunder God".