Euclid (fl. 300 BCE); sometimes called Euclid of Alexandria to distinguish him from Euclid of Megara; was a Greek mathematician; often referred to as the 'father of geometry'. He was active in Alexandria during the reign of Ptolemy I (323-283 BCE).

Hermann of Reichenau (July 18; 1013 - September 24; 1054); also called Hermannus Contractus or Hermannus Augiensis or Herman the Cripple; was a Roman Catholic 11th-century scholar; composer; music theorist; mathematician; and astronomer. He built musical and astronomical instruments and was also a famed religious poet.