Abu Musa (Persian: بوموسی‎) is a 12.8 km² island part of Hormozgan province in Iran. Located in the eastern Persian Gulf, it is part of a six-island archipelago near the entrance to the Strait of Hormuz. Iran's sovereignty of the islands is disputed by the United Arab Emirates.

Abu Musa's inhabitants call it "Gap-sabzu" (Persian: گپ‌سبزو‎), which in Persian means "the great green place." On old maps, the island is called:

But in recent century it is also called Bum Musa, Persian for "the land of Musa/Moses" instead of "Boum-Sou".

As of 2012, the island had about 2,131 inhabitants, making it Iran's smallest county. The city of Abu Musa had 1,953 inhabitants in 2012, up 248 from 2006.

Abu Musa island is 75 km from Bandar Lengeh and 16 km from Strait of Hormuz. It is the farthest island (out of 14 islands of Hormozgan) from the Iranian coast of the Persian Gulf. It's 46 m above the sea. The highest place is the 110-meter Halva mountain. Abu Musa city is the center of the island. The weather in Abu Musa is warm and humid, although, compared to the place in the Persian Gulf, Abu Musa has a better climate and the most diverse ecosystem, but it lacks suitable soil and water for farming leaving fishing as the main industry for locals. It is one of the main ports for exporting oil from Iran. Due to the depth of sea, oil tankers and big ships, have to pass between Abu Musa and Greater and Lesser Tunbs; this makes these islands one of the most strategic points for Iran in the Persian Gulf.

Yaqub ibn Ibrahim al-Ansari, better known as Abu Yusuf (Arabic: أبو يوسف‎) (d.798) was a student of legist Abu Hanifah (d.767) who helped spread the influence of the Hanafi school of Islamic law through his writings and the government positions he held.

He served as the chief judge (qadi al-qudat) during reign of Harun al-Rashid. His most famous work was Kitab al-Kharaj, a treatise on taxation and fiscal problems of the state.

Abu Yusuf lived in Kufa and Baghdad, in what is now modern day Iraq, during the 8th century. His genealogy has been traced back to Sa'd b. Habta, a youth in Medina in the time of the Prophet, and his birth date is estimated based on his the date of his death to be around 113/729CE. Based on anecdotal stories, Abu Yusuf was raised poor but with a ferocious appetite for knowledge. His father disapproved of his academic desires, insisting that he master some trade so as to help make ends meet. While it cannot be fully verified, stories suggest that he complied with his father's wishes, but also kept up his academic studies. His talent and commitment was eventually recognized by Abu Hanifa who became his mentor with Abu Yusuf as his star pupil. He is portrayed as an incredibly studious individual who was unceasing in his pursuit for knowledge and legal understanding. While much of what is known of his early childhood relies on sometimes contradictory anecdotal evidence, it has been verified that he studied religious law and traditions in Kufa and Medina under a number of scholars including Abu Hanifa, Malik b. Anas, al-Layth b. Sa'd and others. Under the guidance of Abu Hanifa, Abu Yusuf achieved incredible success and helped develop and spread the influence of the Hanafi school of Islamic law.