What is the great contribution of Byzantine patriarch Fotis?

Byzantine scholars devoted themselves to the collation of ancient books, among which Fotis, the great Imam (about 820-892), made the greatest contribution. Fotis is an outstanding figure in political and religious circles. He served as the patriarch of Constantinople twice. He reads widely and diligently searches for ancient books. After he became an official, he wrote the "Summary of Books" and collected 280 classic works, which made great contributions to the preservation of ancient books at that time.