Rajab (Arabic: رَجَب‎) is the seventh month of the Islamic calendar. The lexical definition of the classical Arabic verb rajaba is "to respect" which could also mean "be awe or be in fear", of which Rajab is a derivative. This month is regarded as one of the four sacred months in Islam in which battles are prohibited. The pre-Islamic Arabs also considered warfare blasphemous during the four months. Muslims believe Rajab is the month in which ‘Alī ibn Abī Tālib, the first Imam of Shia Muslims and fourth Caliph of Sunni Muslims, was born.