The battle of the Maeander (497 BC) was the first of three battles between Carian rebels and the Persians that eventually disrupted the first major Persian counterattack during the Ionian Revolt.
The revolt broke out in 499, and at first it only involved the Greek cities of Ionia. In 498 the rebels attacked Sardis, capital of the Persian satrapy of Lydia (north of Caria), and in the aftermath of this limited success the Carians decided to join the revolt.
Darius responded to the revolt by sending three commanders to Asia Minor. At first the new Persian commanders met with success. One army, under Daurises, a son-in-law of Darius, moved to the Hellespont and recaptured Dardanus, Abydus, Percote, Lampsacus and Paesus. Daurises was forced to abandon this campaign when news of the Carian revolt reached him. He turned south and began to march across Anatolia towards Caria.
The Carians had advance warning of the Persian attack. They met in council at White Pillars on the River Marsyas, where they decided to make their stand on the south bank of the River Maeander, on their northern border. This would put the river behind the Persians and increase the scale of any potential Carian victory.
Daurises crossed the Maeander close to its junction with the River Marsyas, which flows north into it. According to Herodotus the battle was long and hard fought, but eventually their greater numbers gave the Persians the victory. The Carians were said to have suffered 10,000 casualties, the Persians 2,000, suggesting a fairly even fight at least at the start.
The surviving Carians fled south to the sanctuary of Zeus the God of War at Labraunda, west of the River Marsyas, and at the eastern end of the peninsula that led out to Miletus. They received reinforcements from Miletus, and decided to fight again, but suffered a second, even heavier defeat (battle of Labraunda, 497 BC).