the 800th anniversary of an event

एक घटना की 800वीं वर्षगांठ

English Usage: The city's octocentenary celebrations were filled with historical exhibitions and events.

Hindi Usage: शहर की octocentenary उत्सव ऐतिहासिक प्रदर्शनी और कार्यक्रमों से भरे हुए थे।