In the year 5305, the plague began among the Jews in Thessaloniki, and on the 4th of Av, a fire broke out from the house of Avraham Katlano the spice merchant, and 5,000 Jewish houses were burned within six hours. From the heavens, the blowing winds fought, and about 100 souls were burned, and many synagogues and study halls and endless books. Such a great calamity had never been seen. People fled their property from the fire, far as a bowshot into the fields, but the fire went upon them and burned.
They told me that the day before the fire, a worthless Jew quarreled with the sage Rabbi Yosef ben Lev over a legal ruling he made against him, and he slapped him on the cheek in the presence of the public. When the sage was before the aforementioned spice merchant, he tore his garments and said in a loud voice: "Heaven, see this!" Afterwards, the plague continued until many people were dying each day, reaching 314 in one day, and afterwards the dead decreased each day [(Sha'arei Kedusha 117b)].