The Battle of Marathon (490 BC) was the culmination of King Darius I of Persia's first major attempt to conquer the remainder of Greece and incorporate it into the Persian Empire, to secure the weakest portion of his western border. Most of what is known of this battle comes from Herodotus. Darius first sent Mardonius, in 492 BC, via a land route to Europe to strengthen Persia's hold of Thrace and Macedon, which had been weakened by the Ionian Revolt. Although successful, most of this force perished in a storm off Mount Athos, and the remainder was forced to return to Asia, losing men along the way. In 490 BC, Datis and Artaphernes were sent in a maritime operation to subjugate the Cyclades islands in the central Aegean and punish Eretria and Athens for their assistance in the Ionian revolt. Eretria was besieged and fell; then the fleet landed in Marathon bay. There they were defeated by a small force of Athenian and Plataean hoplites, despite their numerical advantage. The long run of the messenger who conveyed news of the victory to Athens became the inspiration for the marathon race, which was first staged at the 1896 Olympic Games.