1st Seal - the white horse and rider
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 by Rome over a foreign enemy.
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.