Marriage and natural law -- The formation of Christian marriage (i) the essential factor: consent -- The formation of Christian marriage (ii) the institution of obligatory forms -- The sacrament of matrimony -- The contract and the sacrament in Christian marriage -- The church's jurisdiction over matrimonial causes -- The indissolubility of marriage: New Testament teaching -- The indissolubility of marriage: the witness of history (i) from the earliest times until Gratian (1140 A.D.) -- The indissolubility of marriage: the witness of history (ii) from Gratian (1140) to the present day -- Dissolution of non-consummated marriage -- Divorce and remarriage of converts -- The prohibited degrees of kindred and affinity -- Monogamy: second and subsequent marriages.