Original: Nicomachus () (c. 60 c. 120) was an important mathematician in the ancient world and is best known for his works Introduction to Arithmetic (Arithmetike eisagoge) and The Manual of Harmonics in Greek.
Simplified: He was strongly influenced by Aristotle and is best known for his works Introduction to Arithmetic (Arithmetike eisagoge) and The Manual of Harmonics in Greek.