1st seal - the white horse
This rider of this white horse has a bow, which represents weapons of war. A crown is a symbol of a king.
The bow is symbolic of evil intentions. The horse's rider is the first of four riders who each mark the beginning of a sequence of awful times.
White horses were used by victorious Roman Generals in parades called Triumphs. They were an emblem of triumph and power of foreign enemy of Rome.
Background Reading:
Revelation 6:1-2
The 1st Seal the white horse
6 I watched as the Lamb opened the first of the seven seals. Then I heard one of the four living creatures say in a voice like thunder, "Come!" 2 I looked, and there before me was a white horse! Its rider held a bow, and he was given a crown, and he rode out as a conqueror bent on conquest.