19 And of the fourth beast he said that it was exceedingly terrible and strong and mighty, devouring and crushing and trampling with its feet anything that remained. It is the kingdom of the children of Esau. Because after that Alexander the Macedonian became king, the kingdom of the Greeks was founded, since Alexander also was one of them, even of the Greeks. But the vision of the third beast was fulfilled in him, since the third and the fourth were one. Now Alexander reigned for twelve years. And the kings of the Greeks arose after Alexander, being seventeen kings, and their years were two hundred and sixty-nine years from Seleucus Nicanor to Ptolemy. And the Cæsars were from Augustus to Philip Cæsar, seventeen kings. And their years are two hundred and ninety-three years; and eighteen years of Severus.
Source: Demonstrations (New Advent)