In the time of Marius, they adopted the eagle with the thunderbolt in its claws, the emblem of Jove. We are also told that different divisions had certain letters, frequently the name of the commander, inscribed on their standards. This practice was also introduced among the Romans from Greece. It was introduced among the Grecians by Alexander the Great, who observed it among the Persians and other eastern nations. Intoxicated with his triumphs, when he began to claim for himself a divine origin, he caused a standard to be prepared, inscribed with the title of "Son of Ammon," and planted it near the image of Hercules, which, as that of his tutelary deity, was the ensign of the Grecian host. In the same way, the Franks borrowed the eagle from the Romans. The same holds good of the dragon-standard, which, borrowed from the Dacians and other barbarians, was for a long time the standard of the Western Empire, of England, and of Normandy. After the Crusades, however, the cross seems to have taken a prominent place on the standards and banners of European nations. The double-headed eagle of Russia and Austria originated among the Romans, to indicate the sovereignty of the world. When the empire of the Cæsars was divided into the Western and Eastern Empires, this standard continued to be used in both those divisions. From the Eastern Empire it passed into the standard of Russia, on the marriage of Ivan I. with a Grecian princess. From the Western, with the title of Roman Emperor, it passed to Austria. From the above, we cannot fail to perceive, in the past as well as in the present, the tendency, throughout the world, to imitation, in the adoption of national ensigns; also, that the adoption of a particular ensign marked some epoch in the history of the particular nation which adopted it. Thus the various changes in the Roman standard marked the epochs of their conquest, first of the Greeks, then of the Barbarians. The adoption of the eagle by the Franks, their conquest of the Romans. The cross, the era of the Crusades. The double-headed eagle of Russia, the marriage of the Czar to the heiress of the Eastern Empire. That of Austria, the investiture of the emperors of Germany with the title of Roman Emperor. The present union of the crosses of St. George, St. Andrew, and St. Patrick, in the British ensign, reverting to the Crusades, in the members composing it, more directly refers to the union, first, of England and Scotland into the united kingdom of Great Britain, and more recently, to the union of the kingdoms of Great Britain and Ireland, and hence is called _The Great Union_. The eagle of France, marked her republican era.