Battle of Thymbra

The Battle of Thymbra was the decisive battle in the war between Croesus of the Lydian Kingdom and Cyrus the Great of the Achaemenid Empire. Cyrus, having pursued Croesus into Lydia following the drawn Battle of Pteria, met the remains of Croesus' partly disbanded army in battle on the plain north of Sardis in December, 547 BC. Even though Croesus' army was reinforced with many new men, Cyrus utterly defeated it, despite being outnumbered more or less 2:1. This proved decisive, and after the 14-day Siege of Sardis, the city and possibly its king fell, and Lydia was conquered by the Persians.

Cyrus conquered the Kingdom of Media in 550 BCE, which created conflict with the neighboring Kingdom of Lydia. Cyrus's plan was to catch the Lydian king unprepared for battle, but at Thymbra Croesus had more than twice as many men as Cyrus. The Lydians marched out to meet Cyrus and quickly armed all the reserves there, before their allies were to arrive, which they never did. According to Xenophon, Cyrus had 196,000 men in total, which was composed of 31,000 to ~70,000 Persians. This consisted of 20,000 infantry which may have included archers and slingers, 10,000 elite infantry/ cavalry, which may have been the Persian Immortals, plus 20,000 peltasts and 20,000 pikemen. All except the archers and slingers are known to have carried small to large shields. The others were: 42,000 Arabians; Armenians; and Medians, which amounted to 126,000 infantry. There were also 300 camel cavalry, 300 chariots, and 5-6 siege towers, which were known to hold 20 men each. It all amounted to 1,000+ men, partly because there was one citizen, and one soldier on each chariot.

Wikipedia