When James VI and I succeeded as king of England in 1603, he viewed a unified Church of Scotland and England as the first step in creating a centralised, Unionist state. However, the two churches were very different in doctrine; even Scottish bishops violently opposed many Church of England practices. Widespread hostility to reforms imposed on the kirk by Charles I led to the National Covenant on 28 February 1638. Its signatories vowed to oppose any changes, and included Argyll and six other members of the Scottish Privy Council; in December, bishops were expelled from the kirk.