The omega fibula is one of the most widespread and used for a long time. It is originally of Spanish origin and probably spread via the Ibero-Gallic auxiliary troops of the Romans through Gaul to the Rhine, where it was widely used around the birth of Christ, especially in military units.
At the time, Omega clasps could only measure 2 to 6 cm, so the smaller ring clasps were probably used more as (shoe) buckles. For example, leather armor was found in Germanic tombs from the 2nd century, which was closed with Omega clasps attached to the side.
In the Viking Age, in particular, similar fibulas were used. B. the cape was closed. The Omega primer needle is simply inserted into the shoulder through the rolled fabric of the cape and then locked with the round part so that the Omega primer can no longer come off.