Istanbul had been a valuable target since the beginning of the military campaigns of the Muslims. First Muslim Arabs, then Muslim Turks launched numerous military campaigns against Istanbul and besieged the city during some of those campaigns.
The first Muslim military campaigns against Istanbul took place during the reign of Caliphate Uthman. Muawiya, the governor of Syria prepared his navy for the first maritime campaign against Istanbul. This navy fleet beat the Byzantine navy and opened the sea passage to Muslims.
Muslims conducted the first Istanbul siege in 668, during the reign of Muawiya. the siege continued until the spring of 669, but the army couldn’t conquer the city. Epidemics killed many soldiers and army had to withdraw. Ebu Eyyub El Ensari, the flag bearer of the Prophet Mohammed was killed during this siege and buried at the bottom of the city walls. According to a popular rumor, his tomb was found by Sheikh Akshemseddin who had visualized its location in his dream, during the conquest of the city by Sultan Mehmed The Conqueror. A mosque was later built at that location.
After this first campaign, Muawiya sent a new navy in 673. The navy entered the Marmara Sea in 674. but the siege which took 7 years was unsuccessful. Another siege, led by Maslama Bin Abdul Malik from August 716 to September 717 was also unsuccessful. He lost the majority of his troops, because of weather conditions, hunger, illness and attacks by Bulgarian guerillas. Some historical sources mention that the Emperor Leon III opened a mosque for Muslim prisoners of war at the request of Maslama and that he toured the city with Maslama after the siege was lifted.
The last siege by Arabs occured in 781 - 782 by the army under the command of Harun who was the son of the sultan of Abbasi Dynasty, EL Mahdi. harun beat the Byzantine army at Izmit and reached Uskudar and besieged the city. He signed a treaty after siege and returned back home.Harun Ar-Rashid was then crowned as Abbasi Sultan and was honored with "Ar-Rashid" title because his Istanbul campaign.
Besides these sieges there were also other campaigns waged by the musim Arabs against Istanbul.