Christopher Clavius was a prominent 16th-century Jesuit mathematician and astronomer, born on March 25, 1538, in Bamberg, Germany. He is best known for his work on the Gregorian calendar, which was introduced in 1582 to correct inaccuracies in the previous Julian calendar. Clavius played a crucial role in the calendar's development and implementation, helping to align the calendar with the solar year. In addition to his contributions to the calendar, Clavius authored several influential mathematical texts, including works on geometry and algebra. His writings were widely used in European universities and helped to advance the teaching of mathematics during the Renaissance. Clavius passed away on February 6, 1612.