The Emergent Era was the name given by historians of the 23rd century to the period of history from 100,000 to 40,000 years before, or around 98,000 BCE to 38,000 BCE. It followed the Forerunner Era and was followed by the Preserver Era.
The Emergent Era was better known than the previous Forerunner Era, with more known about the civilizations of the time, though there were still many gaps. Despite the tales of fanciful fiction, these ancient cultures had no influence on modern Federation cultures, not until long after their demises.
The Era was characterized by three periods in which large and expansionist civilizations were dominant—the Ena, the djKen and the Querat—each separated by three periods of retrogression, primitivism and a lack of interstellar travel, known as the First, Second and Third Interregnums. (FASA RPG - The Orions module: Book of Common Knowledge)