Samuel haNagid was born into a privileged family that settled in Cordoba. He received a classical education, studying Arabic and the Koran in addition to Torah and halacha. Samuel fled Cordoba for Malaga in 1013 when the Berbers attacked. He opened a spice shop in the port city and resumed his career. Before long he was approached by a maid servant to the vizier of Granada and asked if he would write letters on behalf of her master. He agreed, and his work was so impressive that soon he was promoted to the staff of the King of Granada, where he advanced from tax collector, to secretary, to assistant vizier, to vizier. The Jewish community responded to his success by giving him the title, Nagid, or Prince of Israel. Samuel's responsibilities as vizier involved leading the army of Granada, a task he performed for eighteen years. He's also known for his poetry and a compilation on the halacha entitled Hilchot ha'Nagid. Samuel ha'Nagid died while leading a military campaign circa 1055-56.
Source: This material was originally published in Sparks! - an e-zine for Jewish families located on the Internet at http://www.sparksmag.com