Sunan ad-Darimi

Qatadah (may Allah have mercy on him) said: I asked Sayyiduna Anas bin Malik (may Allah be pleased with him): How many times did the Messenger of Allah (peace and blessings be upon him) perform Hajj? He said: He performed Hajj only once, and performed four ‘Umrahs. The first ‘Umrah was when the polytheists prevented him from performing ‘Umrah (i.e., the ‘Umrah of Hudaybiyyah); the second ‘Umrah was when the treaty was made for the following year (i.e., in Dhu al-Qa‘dah, the year after the Treaty of Hudaybiyyah); the third ‘Umrah was when he distributed the spoils of Hunayn in Dhu al-Qa‘dah; and the fourth ‘Umrah he performed along with his Hajj.