Chronicon Pontificum et Imperatorum by Martin Polonus is in Late Medieval Books.
In the year of our Lord 1264, a comet appeared so remarkable that no one then living had ever seen the like. For, rising in the east with great brightness, it drew a shining tail as far as the middle of the sky towards the west; and although it may perhaps have signified many things in different parts of the world, this one thing is certainly known, that since it lasted for more than three months, when it first appeared Pope Urban began to fall ill, and on the same night on which the pope died [2nd October 1264], the comet disappeared.
Anno Domini 1264. Cometes taın notabilis apparuit, qualem nullus tune vivens ante vidit. Ab oriente enim cum magno fulgore surgens, usque ad medium emisperii versus occidentem comam perlucidam protrahebat, et licet in diversis partibus mundi forte multa significaverit, hoc tamen unum pro certo conpertum est, ut cum plus quam per tres menses duraverit, ipso primo apparente papa Urbanus cepit infirmarı, et eadem nocte qua papa expiravit et cometes disparuit.