Kitab al-tabaqat al-kabir – Ibn Sa’d:
“Verily the Apostle of Allah performed Umrah in the year of al-Hudaybiyah in Dhu al-Qa’dah. He performed Umrah in the year he MADE PEACE WITH THE QURAYSH in Dhu al-Qa’dah.” 
Shaykh Allama shibli Nu’mani:
“The treaty of Hudaibiya holds an especial importance in the history of Islam as it was the stepping-stone to all its future success. That is why the Holy Qur’an speaks of it as a victory, though it was nothing more than a treaty of peace entered into by an apparently defeated party.
Out of the four obligatory duties enjoined by Islam the Hajj or a visit to the Ka’ba had considererable merit. In short various reasons may account for the Prophet’s decision to visit Mecca. That the Quraish might not misconstrue his purpose, he put on the customary robe for offering the Umra and took with him the sacrificial camels.
Moreover, none was allowed to carry arms except a sword, which in Arabia was indispensable part of equipage for the journey. But the sword too was to be kept sheathed all along.
The Mujahirs in general and a large number of the Ansaris had long looked forward to the pious pilgrimage, and so fourteen hundred men set out with the Prophet (p). At Dhu al-Halifa, the preliminary ceremonies connected with sacrifices were performed, i.e., iron rings were put round the necks of the camels signifying that they were meant for sacrifice.
As a precautionary measure, a man belonging to the tribe of Khuza’a, whose conversion to Islam was not known to the Quraish, was sent in advance to bring news of their intentions.
The caravan reached Usfan when the man came up with the news that the Quraish had called together the tribes of ‘Ahabish’ (tribes living round Mecca) and declared that Muhammad (p) would never be allowed to enter Mecca.
In short the Quraish made vigorous preparations to offer resistance. They summoned their allies, who came in great numbers and encamped at a place called Balda, outside Mecca. Khalid Ibn Walid, who had not so far embraced Islam, led a vanguard detachment of two hundred horsemen including Ikrima son of Abu Jahl, and reached Ghamim which lies midway between Rabigh and Juhfa.
The Holy Prophet (p) told the Muslims that the Quraish had sent their vanguard under Khalid, who had reached Ghamim, and that they should by-pass him and turn to the right. When the Muslim army reached near Ghamim, they could see the dust raised by the horsemen of Khalid.
Khalid flew back to the Quraish and informed them that the Muslims had reached Ghamim. The Prophet (p) moved forward and halted at Hudaibiya. Here water was scarce, there was only one well which soon ran dry; but by the miraculous power of the Holy Prophet (p), it was quickly filled with enough water to satisfy their wants.” 
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 Kitab al-tabaqat al-kabir, by Ibn Sa’d, volume 2, page 211
 Sirat-Un-Nabi, by Shaykh Allama shibli Nu’mani, volume 2, Page 132 -135