Postquam defecerunt homines etiam parietes cadunt. Jam ecce desolata, ecce contrita, ecce gemitibus oppressa est, &c.
All this was spoken by Gregory to the people of Rome, who were witnesses of the truth of it. Thus by the plagues of the four winds, the Empire of the Greeks was shaken, and the Empire of the Latins fell; and Rome remained nothing more than the capital of a poor dukedom, subordinate to Ravenna, the seat of the Exarchs.
The fifth trumpet sounded to the wars, which the King of the South, as he is called by Daniel, made in the time of the end, in pushing at the King who did according to his will. This plague began with the opening of the bottomless pit, which denotes the letting out of a false religion: the smoke which came out of the pit, signifying the multitude which embraced that religion; and the locusts which came out of the smoke, the armies which came out of that multitude. This pit was opened, to let out smoke and locusts into the regions of the four monarchies, or some of them. The King of these locusts was the Angel of the bottomless pit, being chief governor as well in religious as civil affairs, such as was the Caliph of the Saracens.
Swarms of locusts often arise in Arabia faelix, and from thence infest the neighboring nations: and so are a very fit type of the numerous armies of Arabians invading the Romans. They began to invade them A.C. 634, and to reign at Damascus A.C. 637. They built Bagdad A.C. 766, and reigned over Persia, Syria, Arabia, Egypt, Africa and Spain. They afterwards lost Africa to Mahades, A.C. 910; Media, Hircania, Chorasan, and all Persia, to the Dailamites, between the years 927 and 935; Mesopotamia and Miafarekin to Nasiruddaulas, A.C. 930; Syria and Egypt to Achsjid, A.C.