Soon after the appointment of Abu-Ubaidah as commander in chief, he sent a small detachment to the annual fair of Abu-al-Qudas (Mass (liturgy)), held at Ablah, near Zahlé east of Beirut. There was a Byzantine and Christian Arab garrison nearby, but the size of the garrison was miscalculated by the Muslim informants. The garrison quickly encircled the small Muslim detachment, but before it was completely destroyed, Khalid came to the rescue of the Muslim army. Abu Ubaidah, having received new intelligence, had sent Khalid. Khalid reached the battlefield and defeated the garrison on 15 October and returned with tons of looted booty from the fair and hundreds of Roman prisoners.