The primary class of the disciples of Pythagoras, who served a five years' probation of silence, and were hence called acousmatici or hearers. According to Porphyry or Porphyrius, a Greek philosopher who lived about 233-306 A.D., they received only the elements of intellectual and moral instruction, and, after the expiration of their term of probation, they were advanced to the rank of Mathematici (see Pythagoras).