»The sun was darkened for seventeen days« (AD 797). An Interdisciplinary Exploration of Celestial Phenomena between Byzantium, Charlemagne, and a Volcanic Eruption
Johannes Preiser-Kapeller|Ewald Kislinger
The blinding of the Byzantine Emperor Constantine VI in Constantinople August 797 and his overthrow by mother Eirene, who then until 802 ruled as first female emperor Eastern Roman Empire, was used legitimation for coronation Frankish King Charlemagne Romans on December 25, 800, contemporaries Western Europe. Some observers West may have even interpreted downfall replacement a woman sign an impending collapse Empire entire world order already expected, based chiliastic calculations. We equally find indications apocalyptic expectations Constantinople, where linked with spectacular celestial manifestation divine disapproval, darkening sun 17 days. In this paper, obfuscation is compared description other atmospheric climatic phenomena 8th 9th century well before after period. addition, natural scientific data to disprove earlier hypotheses physical background event present more probable scenario, i. e., impacts one or volcanic eruptions, phenomena, which provided peculiar framework interpretation events between contemporaries.
Medieval Worlds|arXiv (Cornell University)|Oesterreichisches Musiklexikon online (Institut für kunst- und musikhistorische Forschungen der  Österreichischen Akademie der Wissenschaften)