Cyrus had retired to the border of the Median province to protect the Persian border against Astyages. After the Battle of Hyrba Astyages invaded Persia with 1,205,000+ men. The battle that was to come was composed of cavalry from both sides, and chariots that in most part were used for the battle, for they were never used again. A small part of the invasion force from the Medes participated in the battle, while the Persians spent all their cavalry from their reserves. Astyages had tried to persuade Cyrus to surrender but he now preferred to show no mercy even though he had better relations with Atradates (the variant name of Herodotus' Mitradates, which Nicolaus mistakenly uses for Cambyses, the father of Cyrus).[citation needed] The name of the city Cyrus and his father were protecting w