By 800 almost everyone was Christian. They were called Gaels and they spoke the Gaelic language. In 795, the Vikings, sailors from Scandinavia, invaded and stole from many towns. The Vikings ruled over Irish kings. They built Dublin and other cities and towns on the coast. In 902 the Christian Irish armies pushed out the Vikings, but in 917 the Vikings came back to start a new kingdom of Dublin. Over time, Vikings started new kingdoms. In the 1000s and 1100s, the Vikings either left or became part of Irish culture.