The Surah has been so entitled after the word Quraish in the very first verse.
Period of Revelation
Although Dahhak and Kalbi regard it as a Madani Surah, yet a great majority of the commentators are agreed that it is Makki, and a manifest evidence of this are the words Rabba hadh-al-Bait (Lord of this House) of this Surah itself. Had it been revealed at Madinah, the words "this House" for the Ka'bah could not be relevant. Moreover, its subject matter so closely relates to that of Surah Al-Fil that probably it was revealed immediately after it, without any other Surah intervening between them. On the basis of this very relevance, some of the earliest scholars regard the two Surahs as one entity. This view is strengthened by the traditions which say that in the Quran copy belonging to Hadrat Ubayy bin Ka'b these two were written as one Surah, i.e. without the insertion of the Bismillah between them. Furthermore, Hadrat Umar had once recited the two Surahs as one in the Prayer. But this view is not acceptable because in the Quran copy which Hadrat Uthman (may Allah bless him) had got written down officially by the cooperation of a large number of the Companions and sent to the centers of Islamic lands, the Bismillah was written between these two Surahs, and since then these two have been written as separate Surahs in all the copies of the Quran everywhere in the world. Moreover, the style of the two Surahs is so different that they manifestly appear as two separate Surahs.
To understand the Surah well it is essential that one should keep the historical background relevant to the contents of this Surah and of Surah Al-Fil in view.