First - there was no formal or recognized sacrament of matrimony until the 12th century.  It took centuries for this sacrament to become part of church practice and Trent had to clarify this sacrament in the 16th century.  The Church now understands and explains this sacrament as between the couple - they do the sacrament....the minister is only the church's official witness - the couple actually marry each other; it is their action with God's assistance.  This sacramental understanding is not what you would find at the time of Trent.