Europe: blood-red clouds to the north on 21 September 1098, then the sky burning on 25 to 27 September

Fritz 1873: 1098 Sept 21 (Gregorian 27), Germany: 'in the night blood-red clouds toward midnight [north]' (Chronik von Augsburg); Sept 25, central Europe: the sky glowing at night in many places (Lycosthenes); Sept 26, central France: aurora (Perrey); Sept 27, Angers: aurora (the two chronicles of St Aubin of Angers); the sky seen burning in many places (Sigebert of Gembloux, a contemporary). Caveat: the Augsburg chronicle may be a later compilation; Sigebert and the Angers annals are the strongest witnesses.