Phraates II of Parthia, son of Mithridates I of Parthia (171–128 BC), the conqueror of Babylon, ruled the Parthian Empire from 138 BC to 128 BC. He was attacked in 130 BC by Antiochus VII Sidetes (138–129 BC), ruler of the Seleucid Empire. Antiochus VII, however, after great initial success, was defeated and killed in battle in Media in 129 BC, which ended the Seleucid rule east of the Euphrates. Meanwhile Parthia was invaded by the Scythians (the Tochari of Bactria), who had helped Antiochus VII. Phraates II marched against them, and was defeated and killed in a great battle inside and around Media.