The eastern Caucasus range became the main theatre of the Arab–Khazar conflict, with the Arab armies aiming to gain control of Derbent (in Arabic, "Bab al-Abwab" or "Gate of Gates") and the Khazar cities of Balanjar and Samandar. Their locations have yet to be established with certainty by modern researchers, but both cities are referred to as Khazar capitals by different Arab writers, and may have functioned as winter and summer capitals respectively. It was only later, under the impact of the Arab attacks, that the Khazars moved their capital further north, to Atil (Arabic "al-Bayda") on the mouths of the Volga.