1096: celestial phenomena and the announce of the First Crusade
On 1096, almost at the end of the winter, a council of great lords took place in Paris, under the guidance of Hugues de Vermandois. His brother, Philip I king of France, attended the conference held to organize the crusade, the new task (taking the cross and passing to Asia) just called by pope Urban II on 1095 in Clermont Ferrant, together with king Philip's excommunication due to his extra-marriage to beautiful Berta, wife to Foulques dit le Querelleur.
During the conference lords and people were entertained by a stunning total lunar eclipse (it took place in the middle of the night, on February 11th) [1]. Other uncommon celestial phenomena followed during the next months.
In the charming french countryside, on a quiet evening after a hot day - it was the very beginning of spring - peasants were shocked by observing that the north horizon went on flames as the nearby villages in that direction were on fire. Actually no burning happened. Could Guibert de Nogent possibly record an aurora observation?
Some days later, it was April, lots of stars were seen falling from the sky in the middle of the night [2].
The flaming horizon phenomenon repeated at last once in 1098 in the same regions of the _orbis terraqueus_ . In the Saxon Chronicles we read: "Before S. Micheal's Mass the heaven appeared almost all night as if it were burning." In 1096 sun spots were also seen, naked eye, on the solar disk [3].
Light bibliography for essential argonauts:
[1] https://eclipsewise.com/lunar/LEprime/1001-1100/LE1096Feb11Tprime.html
[2] Guibert De Nogent, Dei gesta per Francos, Liber II, Caput VIII. XVII
"Quadam autem aestivi diei vespertina irruente hora, tanta ab aquilonis plaga efflagratio apparuit ut plurimi e domibus suis sese proriperent, quaerentes quinam hostes provincias suas adeo gravi ambustione vastarent. Visae sunt praeterea non multo post tempore, mense Aprili stellae noctu, ac si pluvia dense de coelestibus labi."
https://remacle.org/bloodwolf/historiens/guibertdenogent/croisade2.htm
[3] Hunters for coincidence between solar spots and aurorae wrote down it happened around Sun-spot maximum.
Johnson S. J., Coincidence of sun-spots and aurorae in olden times, Monthly Notices of the Royal Astronomical Society, Vol. 40, p. 561- 563.