Earliest day on which Sham el-Nessim can fall, while May 9 is the latest; celebrated on Monday after the Orthodox Easter (Egypt)

Sham Ennessim is a festival marking the beginning of spring, celebrated by Egyptians of all religions. It is an official public holiday in Egypt. Sham Ennessim always falls on Easter Monday, which is the day after Easter, in accordance with the Coptic Orthodox Church. The Arabic name Sham Ennesim translates into "Smelling/Taking In the Zephyrs".

Eastern Christianity comprises Christian traditions and church families that originally developed during classical and late antiquity in the Eastern Mediterranean region or locations further east, south or north. The term does not describe a single communion or religious denomination. Eastern Christianity is a category distinguished from Western Christianity, which is composed of those Christian traditions and churches that originally developed further west.

Easter, also called Pascha or Resurrection Sunday, is a Christian festival and cultural holiday commemorating the resurrection of Jesus from the dead, described in the New Testament as having occurred on the third day of his burial following his crucifixion by the Romans at Calvary c. 30 AD. It is the culmination of the Passion of Jesus, preceded by Lent, a 40-day period of fasting, prayer, and penance.

Egypt, officially the Arab Republic of Egypt, is a country spanning the northeast corner of Africa and southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to the north, the Gaza Strip of Palestine and Israel to the northeast, the Red Sea to the east, Sudan to the south, and Libya to the west; the Gulf of Aqaba in the northeast separates Egypt from Jordan and Saudi Arabia. Cairo is the capital, largest city, and leading cultural center, while Alexandria is the second-largest city and an important hub of industry and tourism. With over 107 million inhabitants, Egypt is the third-most populous country in Africa and 15th-most populated in the world.