Dhul Qa`dah

Dhu'l-Qi'dah, Dhu'l-Qa'dah, or alternatively Zulqida (Arabic: ذو القعدة‎‎, also transliterated Ḏū l-Qaʿdah, IPA: [ðʊlˈqɑʕda]) is the eleventh month in the Islamic calendar. It is one of the four sacred months in Islam during which warfare is prohibited, hence the name "Master of Truce".

The most correct and most traditionally widespread transliteration of the month according to the thirteenth century Syrian jurist al-Nawawi is Dhu'l Qa'dah. Al-Nawawi also mentions that a smaller group of linguists allow the transliteration Dhu'l-Qi'dah, however. In modern times, it is most commonly referred to as Dhu'l Qi'dah although this is neither linguistically nor historically the strongest position.

The Islamic calendar is a lunar calendar, and months begin when the first crescent of a new moon is sighted. Since the Islamic lunar calendar year is 11 to 12 days shorter than the tropical year, Dhu'l-Qi'dah migrates throughout the seasons. The estimated start and end dates for Dhu'l-Qi'dah, based on the Umm al-Qura calendar of Saudi Arabia, are:

In Dhu al-Qi'dah (Islamic month), there will be fight among the tribes, Muslim pilgrims will be looted and there will be a battle in Mina in which many people will be slain and blood will flow until it runs over the Jamaratul Aqba (one of the three stone pillars at Mina). The man they seek will flee and will be found between the Rukn (a corner of the Kaaba containing the Black Stone) and the Maqam of Prophet Abraham (near Ka'ba). He will be forced to accept people's Bay'ah (being chosen as a Leader/Caliph). The number of those offering Bay'ah will be the same as the number of the people of Badr (Muslim fighters who participated in the Battle of Badr at time of Prophet Mohammad). Then, the dweller of Heaven and the dweller of the Earth will be pleased with him.

...
Wikipedia