In June 2005, Mahmoud Ahmadinejad's meteoric rise from mayor of Tehran to president of one of the most influential countries in the Middle East took everyone by surprise. One of the main reasons for the astonishment was that so little was known about him.

One recently published claim about his background comes from an article in the Daily Telegraph. Entitled "Mahmoud Ahmadinejad revealed to have Jewish past", it claims that his family converted to Islam after his birth. The claim is based on a number of arguments, a key one being that his previous surname was Sabourjian which "derives from weaver of the sabour, the name for the Jewish tallit shawl in Persia".

Professor David Yeroshalmi, author of The Jews of Iran in the 19th century and an expert on Iranian Jewish communities, disputes the validity of this argument. "There is no such meaning for the word 'sabour' in any of the Persian Jewish dialects, nor does it mean Jewish prayer shawl in Persian. Also, the name Sabourjian is not a well-known Jewish name," he stated in a recent interview. In fact, Iranian Jews use the Hebrew word "tzitzit" to describe the Jewish prayer shawl. Yeroshalmi, a scholar at Tel Aviv University's Center for Iranian Studies, also went on to dispute the article's findings that the "-jian" ending to the name specifically showed the family had been practising Jews. "This ending is in no way sufficient to judge whether someone has a Jewish background. Many Muslim surnames have the same ending," he stated.

Upon closer inspection, a completely different interpretation of "Sabourjian" emerges. According to Robert Tait, a Guardian correspondent who travelled to Ahmadinejad's native village in 2005, the name "derives from thread painter – sabor in Farsi – a once common and humble occupation in the carpet industry in Semnan province, where Aradan is situated". This is confirmed by Kasra Naji, who also wrote a biography of Ahmadinejad and met his family in his native village. Carpet weaving or colouring carpet threads are not professions associated with Jews in Iran.

According to both Naji and Tait, Ahmadinejad's father Ahmad was in fact a religious Shia, who taught the Quran before and after Ahmadinejad's birth and their move to Tehran. So religious was Ahmad Sabourjian that he bought a house near a Hosseinieh, a religious club that he frequented during the holy month of Moharram to mourn the martyrdom of Imam Hossein.

Moreover, Mahmoud Ahmadinejad's mother is a Seyyede. This is a title given to women whose family are believed to be direct bloodline descendants of Prophet Muhammad. Male members are given the title of Seyyed, and include prominent figures such as Iran's supreme leader Ali Khamenei. In Judaism, this is equivalent to the Cohens, who are direct descendants of Aaron, the brother of Moses. One has to be born into a Seyyed family: the title is never given to Muslims by birth, let alone converts. This makes it impossible for Ahmadinejad's mother to have been a Jew. In fact, she was so proud of her lineage that everyone in her native village of Aradan referred to her by her Islamic title, Seyyede.

The reason that Ahmadinejad's father changed his surname has more to do with the class struggle in Iran. When it became mandatory to adopt surnames, many people from rural areas chose names that represented their professions or that of their ancestors. This made them easily identifiable as townfolk. In many cases they changed their surnames upon moving to Tehran, in order to avoid snobbery and discrimination from residents of the capital.

The Sabourjians were one of many such families. Their surname was related to carpet-making, an industry that conjures up images of sweatshops. They changed it to Ahmadinejad in order to help them fit in. The new name was also chosen because it means from the race of Ahmad, one of the names given to Muhammad.

According to Ahmadinejad's relatives the new name emphasised the family's piety and their dedication to their religion and its founder. This is something that the president and his relatives in Tehran and Aradan have maintained to the present day. Not because they are trying to deny their past, but because they are proud of it.