A folio page from the astronomical work, Kitab-i viladat-i Iskandar, the personal horoscope of Iskandar Sultan, grandson of Timur, who ruled the province of Fars in Iran from 1409 to 1414. The folio displays the position of the planet Mercury in the sixth house at the moment of the Prince's birth. The belief was that Mercury in this house often signifies a highly organized mind.