Orb

ORB -  The ball as a symbol of the cosmos, or of the universe as a harmonious whole, is derived from the ancient Romans, who associated it with Jupiter and, hence, with the emperor as his earthly representative.

Christians adapted the symbol by setting a cross above the ball to signify the world dominated by Christianity.   Rulers were often depicted with the orb, but the first to hold it in hand at his coronation was the Holy Roman emperor Henry II in 1014; thereafter the “imperial apple” became an important emblem of the royal power invested in the monarch.

Holding the world in one's hand, or more ominously, under one's foot, has been used as a symbol since antiquity.  With the growth of Christianity in the 5th century, the orb (in Latin scriptures orbis terrarum, the 'world of the lands', hence the word "orb") was topped with a cross, symbolizing the Christian God's dominion over the world.  The emperor held the world in his hand, to show that he ruled it on God's behalf.  To non-Christians already familiar with the pagan globe, the surmounting of a cross sent a message about the triumph of Christianity.  In medieval iconography, an object's size, relative to that of nearby objects, indicated its relative importance; so the world was small and the one who held it was large, to emphasize the nature of their relationship.  Although the globe symbolized the entire Earth, its use spread among many Christian rulers (some of them not even sovereign) who reigned over small parts of the earth.