Revelation 6:2

And I saw, and behold a white horse, and he that sat on him had a bow — This colour, and the bow shooting arrows afar off, betoken victory, triumph, prosperity, enlargement of empire, and dominion over many people.

Another horseman, indeed, and of quite another kind, appears on a white horse, Revelation 19:11. But he that is spoken of under the first seal must be so understood as to bear a proportion to the horsemen in the second, third, and fourth seal.

Nerva succeeded the emperor Domitian at the very time when the Revelation was written, in the year of our Lord 96. He reigned scarce a year alone; and three months before his death he named Trajan for his colleague and successor, and died in the year 98. Trajan's accession to the empire seems to be the dawning of the seven seals. And a crown was given him — This, considering his descent, Trajan could have no hope of attaining. But God gave it him by the hand of Nerva; and then the east soon felt his power. And he went forth conquering and to conquer — That is, from one victory to another. In the year 108 the already victorious Trajan went forth toward the east, to conquer not only Armenia, Assyria, and Mesopotamia, but also the countries beyond the Tigris, carrying the bounds of the Roman empire to a far greater extent than ever. We find no emperor like him for making conquests. He aimed at nothing else; he lived only to conquer. Meantime, in him was eminently fulfilled what had been prophesied of the fourth empire, Daniel 2:40, Daniel 7:23, that he should "devour, tread down, and break in pieces the whole earth."