Comet seen for 40 days in Constantinople & Jerusalem

Summary:
While Alexios I was preparing defences against the attack of Bohemond, a great comet appeared in the sky for 40 days. He asked Basileios, the eparch of the city who had a reputation as an astrologer, what the comet meant. Basileios saw St Ioannes the Evangelist in a dream, and he told him that it signified the Norman invasion of Bohemond, while its extinction meant that the invasion would fail. The comet was also seen by Fulcher of Chartres in Jerusalem, together with other phenomena in the sky during February and March 
Dates:
1106 February-March: 
Emperor Alexios I Komnenos (Alexios 1)
  • He prepared defences against Bohemond 61, strengthening fortifications, taking Eirene 61 with him while there was still no fighting; he asked Basileios 233 about a comet, and was told that it referred to the attack of Bohemond, while its extinction meant that the attack would fail (:) Anna Komnene 367.61-369.16
Basileios, eparchos of the city and astrologer (Basileios 233)
  • He was asked by Alexios 1 about the meaning of a great comet that appeared in early 1106; he saw St Ioannes the Evangelist in a dream, and he told him that it signified the Norman invasion of Bohemond 61; its extinction meant that the invasion would fail (:) Anna Komnene 368.89-369.16
Fulcher of Chartres, historian (Fulcher 101)
  • He was terrified by an earthquake on Christmas eve, puzzled by a comet which appeared in February and lasted some 50 days, and impressed by a celestial phenomenon which seemed to show multiple suns and then by a a shower of stars (:) Fulcher of Chartres 2.34.3-2.35.5