Musannaf Ibn Abi Shayba 36:312

Ubayd Allah ibn Musa narrated to us, from Musa ibn Ubaydah, from Iyas ibn Salamah, from his father, who said: We went out with the Messenger of Allah (may Allah bless him and grant him peace) on the expedition of al-Hudaybiyyah. We slaughtered one hundred camels, and we were seventeen hundred [men], and with them was the equipment of weapons, men, and horses. And among his camels was a male camel. He descended at al-Hudaybiyyah, and the Quraysh made a peace treaty with him that this sacrificial animal’s place of slaughter is where we have detained it.