In ancient times, a garland of this sort was given to the victor in public games which were usually played before the King. The garland was a symbol of excellence and signified that the person who wore it had prevailed over all of the competition. A modern day example of this type of commendation would be the winner of gold medal in the Olympics. The Apostle Paul made mention of this type of crown in I Cor. 9:24 - 25. In that passage, the race (game) was ran with the understanding that only one received the prize (the crown). The crown there is the garland of victory (stef '-an-os), not the headdress (diadem) of a ruler.
In antiquity, the diadem was a blue band with white markings which was used by the Kings of Persia to bind the turban to their heads. It was the article which distinguished the king from all others who wore turbans. Some diadems also incorporated jewels and precious stones in their makeup, but were not crowns in the sense that westerners usually think of them.
The primary difference between the garland and the diadem is that the garland represents an honorary title accompanyed by an exhalted position. It however, lacks the civil or political authority and power which is characteristic of the diadem. There are only three instances in the Book of Revelation where the word, "crown" (diadem), the ornamental headdress of royalty, is referred to: the "seven crowns" of the dragon (12:3); the "ten crowns" of the beast (13:1); and the "many crowns" of Jesus, at His revelation (19:12). All other references to crowns in the book, are to the garland of victory.