Even in England, in the medieval days, all it required for a couple to get married was a solemn vow of marriage to each other, followed by the consummation. No witness no clergy, that was it, but the wise bride did get herself some witnesses, incase the groom denied it later . There are several very famous cases in England, one which brought Richard III to the throne, as he alleged that his brother Edward IV had been married to Eleanor Butler before he married Elizabeth Woodville. In that case there was allegedly one witness to the marriage.