After Matthew, Mark and Luke described a miracle in which Jesus calmed a storm, they each described a miracle in which Jesus healed a man possessed by demons.
As explained in the Gospel of Mark:
When he saw Jesus from a distance, he ran and fell on his knees in front of him. He shouted at the top of his voice, "What do you want with me, Jesus, Son of the Most High God? In God's name don't torture me!" For Jesus had said to him, "Come out of this man, you impure spirit!"
Then Jesus asked him, "What is your name?"
"My name is Legion," he replied, "for we are many." And he begged Jesus again and again not to send them out of the area.
A large herd of pigs was feeding on the nearby hillside. The demons begged Jesus, "Send us among the pigs; allow us to go into them." He gave them permission, and the impure spirits came out and went into the pigs. The herd, about two thousand in number, rushed down the steep bank into the lake and were drowned.
- Mark 5:1-13, NIV translation.
In some manuscripts, Gerasenes is referred to as Gadarenes or Gergesenes. Matthew mentions that there was also a second demon-possessed man who was healed during this miracle.
Read more in the book Jesus the Miracle Worker: The 46 miracles of Jesus explained in chronological order (The Jesus Books) -- now available at amazon.