The fibulae represent an archaeological material with an essential chronological significance. The present study represents an attempt of analyzing the Trajanic fibulae from the forts of Dacia, based on the fibulae from the stratigraphic context, operating as well with the analogies from the civil centers well documented under stratigraphic aspect, and also with analogies from other provinces. We used furthermore, where we had been able to, the association with other categories of materials, as terra sigilata or coins. Our approach regards, moreover, the period of usage of several "types" (strong profilated fibulae, or Kraftig Profilierte, and the so-called "nee" fibulae, etc.) which may vary between 80 and over 100 years, our researched working, actually, with the short usage "variants".