When did the Muslims get Palestine?

The Muslims first conquered Jerusalem and entered Palestine during the second Rightful Caliph Hazrat Omar (RAU) without bloodshed.

The Muslims first conquered Palestine in the reign of the Second Rightful caliph Hazrat Omar Farooq (RAU) who assumed power on 23rd August,632 AD.

Background; Allah Almighty sent about 1,24,000 Prophets (May peace be upon them all) for the guidance of humans. By faith, the Muslims believe in all these holy Prophets. Hazrat Muhammad (SAW) being the last one. He was the descendent of Hazrat Ismael (AS) the elder son of Hazrat Abraham (AS).

Most of the Prophets were from the progeny of Hazrat Jacob (AS) known as Israel, the younger son of Hazrat Abraham (AS), Hazrat Izak (AS). They came to guide the Israelites (the Jews) to the right path. They were born and buried in Palestine and surrounding areas of Syria and Egypt. The Jews inhabited these areas. The Jews were many times pushed out of Palestine, or enslaved by the Roman Empire or Persians for the reasons best known to the Jews.

Conquest of Jerusalem (The main city of Palestine) by the Muslim:
The holy city of Jerusalem was ruled by the Christians. The entry of the Jews in Jerusalem was banned. The Muslim forces led by Hazrat Abu Ubaida and Hazrat Khalid bin Waleed seiged Jerusalem in November 636. After a few months the Christian Patriarch Sophronius agreed to surrender on the condition that the Second Rightful Caliph Hazrat Omar (RAU) should personally come to sign the agreement. Hazrat Omar (RAU) travelled from Madina to Jerusalem and signed the agreement. Jerusalem fell to the Muslims without any bloodshed in April 637 AD. The Jews were permitted to enter Palestine, live there peacefully and worship according to their own religion. Thus the Christians, the Jews and the Muslims lived peacefully in this city which is sacred for the Jews, the Christians and the Muslims alike. The Dome of the Rock was built by Caliph Waleed bin Abdul Malik. (Husnain Haikal-Tabari-Ibn i Kaseer)
Caliph Omar of the Rightly-Guided Caliphate conquered Palestine from the Byzantine Empire. The Community Answer is a little confusing. While it is true that Jerusalem was entered without bloodshed, the conquest of Palestine was actually quite violent. The critical battle was the Battle of Ajnadayn (in Beit Guvrin, Israel today) in 634 C.E., but others included the Battle of Dathin (in Gaza) in 634 C.E. and the Battle of Pella (in Jordan) in 635 C.E.

The Muslims lost Palestine while there were the Crusader Kingdoms (1099-1291). The Muslims regained Palestine afterwards by the Ayyubid Caliphate, led by Saladdin. The Muslims lost Palestine again in 1919 when the British took over Mandatory control. The Muslims have regained power over Palestine only in certain areas, such as the Gaza Strip and the West Bank Zone