In 625, Heraclius dispatched to the steppes his emissary, named Andrew, who promised to the Khagan some "staggering riches" in return for military aid.[5] The khagan, on his part, was anxious to secure the Chinese-Byzantine trade along the Silk Route, which had been disrupted by the Persians in the aftermath of the Second Perso-Turkic War.[6] He sent word to the Emperor that "I shall take revenge on your enemies and will come with my valiant troops to your help".[7] A unit of 1,000 horsemen fought their way through Persian Transcaucasia and delivered the Khagan's message to the Byzantine camp in Anatolia.