Minn. Stat. § 517.01: CIVIL MARRIAGE CONTRACT.

A civil marriage, so far as its validity in law is concerned, is a civil contract between two persons, to which the consent of the parties, capable in law of contracting, is essential. A lawful civil marriage may be contracted only when a license has been obtained as provided by law and when the civil marriage is contracted in the presence of two witnesses and solemnized by one authorized, or whom one or both of the parties in good faith believe to be authorized, so to do. Marriages subsequent to April 26, 1941, not so contracted shall be null and void.