Adolphus established colonies that were significant for spiritual reasons. Denominations started as groups split from the church. The greatest attacks on the church came from within. The Age of Reason was also known as the Enlightenment. The Renaissance featured the key figure of artist and inventor Leonardo da Vinci. Blaise Pascal made an important contribution to mathematics. Christianity was dominated by Catholicism for over a thousand years. Voltaire significantly challenged the church. The Thirty Years' War started in 1618 and was a religious civil war in Europe.