What was the Greek Earthquake of 856?

There probably wasn't a significant Greek earthquake of 856, but there was an Iran earthquake on 22 December 856 that killed 200,000 people. It was probably strongly felt throughout the region, and many people may have thought it occurred near them. See US Geological Survey National Earthquake Information Center Most Destructive Earthquakes at http://earthquake.usgs.gov/regional/world/most_destructive.php