The little-known Battle for Raichur (1520), waged between Krishna Raya of Vijayanagara and Sultan Isma'il ‘Adil Shah of Bijapur, saw a number of firsts in South Asian history: the earliest significant appearance of cannon—whether used offensively as field artillery, or used defensively on the battlements of forts—the earliest known appearance of matchlock firearms, and the first significant use of European mercenaries. It followed the merging of new gunpowder technologies after engagements between Portuguese and Ottoman navies off the Konkan coast. Notably, the side that lost the battle, Bijapur, had the superior firepower. The essay also explores the extraordinary round of diplomacy that followed the battle and the humiliating demands Krishna Raya imposed on the defeated sultan. These demands, and the military and diplomatic manoeuvres that accompanied them, likely sowed the seeds for Vijayanagara's spectacular defeat and destruction forty-five years later, at the Battle of Talikota.