Guidobaldo del Monte (11 January 1545 - 6 January 1607, var. Guidobaldi or Guido Baldi), Marquis del Monte, was an Italian mathematician, philosopher and astronomer of the 16th century. Wikipedia
The definitive Wikipedia entry for Guidobaldo del Monte. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Guidobaldo_del_Monte