I have always seen Moiraine, Siuan and Tamra as the three wise men from the Bible. The three wise men was magi, astrologers and mystics and Moiraine, Siuan and Tamra are three mages who after a sign start looking for the chosen child, now off course only Moiraine and Siuan continue on this path and Tamra get murdered but in the beginning there was three of them.