Cometary records revise Eastern Mediterranean chronology around 1240 CE

TL;DR

This paper uses cometary records and historical analysis to precisely date the death of Empress Eirene in 1240, refining the Eastern Mediterranean chronology around that period.

Contribution

It critically reassesses historical comet records and establishes a more accurate date for Eirene's death, enhancing understanding of 13th-century Eastern Mediterranean history.

Findings

Eirene died in summer 1240 based on comet observations.

The 3 June 1239 record was not a comet, contrary to previous assumptions.

The 31 January 1240 record was confirmed as a comet, aligning with historical accounts.

Abstract

Eirene Laskarina, empress of John III Batatzes of the exiled Byzantine Empire of Nicaea (1204--1261 CE), was an important Eastern Mediterranean figure in the first half of the thirteenth century. We reassess the date of Eirene's death, which has been variously dated between late 1239 and 1241, with the understanding that narrowing the range in which this event occurred contributes much to understanding the political situation in the area around 1240. George Akropolites, a famous official of the Empire, gives an account that connects Eirene's death to a comet that appeared "six months earlier", thus pointing to two comet candidates that were visible from the Eastern Mediterranean between 1239 and 1241, one recorded on "3 June 1239" and the other on "31 January 1240". Recent historians prefer the former, based on historical circumstances and without a critical assessment of the comet records. We revisit the historical records and reveal that the "3 June 1239" candidate was not a comet. On the other hand, the other candidate, sighted on "31 January 1240", was a comet, as supported by multiple historical records in multiple regions, and is also a good fit with Akropolites's narrative. Therefore, we conclude that Eirene died six months after the comet that was seen on 31 January 1240, which places her death in the summer of 1240. Given that the date of her death is crucial for determining some other contemporary events across the Eastern Mediterranean, our results offer a solid basis for further research on the thirteenth-century Eastern Mediterranean.