The Prologues are much older. I don't know who started writing them, but I guess it was a continuous work throughout the centuries.
In the Preface, Saint Nikolaj writes(translated from the Romanian version):
"These Prologues are called from Ohrid to be distinguished from the ancient Slavonic Prologues which unfortunately, because of the archaic language, have become inaccessible to the Slavic Orthodox people nowadays. The difference between the two Prologues is not an essential one, but more a technical one, which the more experienced readers will easily spot themselves, besides the language difference and the difference of the arrangement of the teaching material, the biggest difference could consist of the including of many saints which came from the different Orthodox people in the last two hundred years, and there is now way they could be in the Slavonic or the Greek Prologues."
So the Prologues have to be at least older than 1700's.