Nicomachus was born around 60 CE in Gerasa, a Greek speaking city in Roman Syria, in what is now Jarash, Jordan, and is thought to have died around 120 CE; both dates are approximate, established from internal references in his surviving work rather than direct biographical record. He wrote within the Neopythagorean movement, a revival of interest in Pythagoras's teaching on number as the underlying structure of reality that flourished in the early centuries of the Roman era, presenting himself as transmitting and systematizing that older tradition rather than founding a new one.
Little else of his personal life survives. His influence is known almost entirely through the survival and continued use of his written work: his Introduction to Arithmetic was translated into Latin by the North African writer Apuleius within about a generation of his death, an unusually fast and significant sign of the work's early reputation, and it went on to serve as the standard arithmetic textbook of the Latin speaking world through the medieval period, long after the original Greek Neopythagorean context that produced it had faded.
Gerasa itself, part of the Decapolis, a loose league of ten Greek influenced cities in the Roman Near East, gave Nicomachus a specifically Hellenized cultural setting distinct from the older centers of Greek Pythagorean study in southern Italy, illustrating how far the tradition Pythagoras founded had spread and taken root across the eastern Mediterranean world by the first century of the common era.