Musannaf Ibn Abi Shayba 28:656

Yunus ibn Muhammad narrated to us, he said: Mujamma' ibn Ya'qub narrated to us, he said: My father informed me, from his uncle 'Abd al-Rahman ibn Yazid, from Mujamma' ibn Jariyah, he said: We witnessed al-Hudaybiyah with the Messenger of Allah, may Allah bless him and grant him peace, and it was divided into eighteen shares. The army was one thousand five hundred, [including] three hundred cavalrymen. So the cavalryman had two shares.