Apologies that this is very late for most, I came across it today when I was checking my reader. I have been offline during most of Hajj Andrew
One of the most important dates in the Islamic calendar is Eid al-Adha (‘Festival of Sacrifice.’) Also known as the Greater Eid, the day comes at the end of Hajj, the annual religious pilgrimage to the holy city of Mecca in Saudi Arabia.
The precise date of Eid varies from year to year because its calculation comes from the Islamic calendar, which is lunar. It falls on the 10th day of the Islamic month of Dhu al-Hijjah, which, in most Muslim countries, falls on 1 September in 2017 and lasts for four days. Pakistan marks Eid on September 2.[ ]
Source: Hajj 2017: When is the Eid al-Adha Holiday? – The Muslim Times