Apple of Discord

The Apple of Discord (Ancient Greek: μῆλον τῆς Ἔριδος) was a golden apple dropped by Eris, the goddess of strife, at the wedding of Peleus and Thetis in the Greek myth of the Judgement of Paris. It sparked a vanity-fueled dispute among Hera, Athena, and Aphrodite that eventually led to the Trojan War.

In common parlance, the apple of discord is the core, kernel, or crux of an argument, or a small matter that could lead to a bigger dispute.