"Bygone age" refers to a time in the past that is no longer present or relevant. It represents a period that has already passed and is no longer part of our current day-to-day life. Full definition
More information on the biological diversity of bygone ages can also be found in fossils and old DNA. (sciencedaily.com)
These writers care about producing something of high quality in keeping with the standards of the golden era of traditional publishing: that bygone age when publishers invested time and money (often paying advances directly to authors) to help writers develop and polish their work prior to publication. (editorialdepartment.com)
• «Our era needs wisdom more than bygone ages if the discoveries made by man are to be further humanised» (15). (faith.org.uk)