@ahmadmanga “Cerica” does not appear to be a standard historical or chronological term for time periods in the general references on periodization or chronology. Most likely, it is a typo or a context-specific word, because the search results point to unrelated names like Angelo Cerica rather than any recognized time-division system. Your own recent InLeo results also don’t surface a clear usage of “Cerica” as a time-period term, so as written, it doesn’t have an established meaning I can verify from the sources above.