1835 Marriage Act
1835 Marriage Act is in 1800-1850 Act of Union, Trafalgar and Waterloo.
In Aug 1835 the 1835 Marriage Act made marriage between those of certain degrees of affinity (in-laws) and consanguinity (blood) as defined in the Anglican Book of Common Prayer illegal including marrying the spouse of one's deceased relative. Those with sufficient funds could overcome the prohibition by marrying abroad. Gretna Green, Dumfrieshire also appears to have been outside the jurisdiction of the Act.
On 28 Sep 1840 George Edward Waldegrave 7th Earl Waldegrave (age 24) and Frances Braham Countess Waldegrave (age 19) were married at Gretna Green, Dumfrieshire thereby avoiding the constraint of the 1835 Marriage Act. He being the legitimate younger brother of her first husband John James Waldegrave; an example of Married to Two Siblings. He the son of John James Waldegrave 6th Earl Waldegrave. He a great x 4 grandson of King James II of England Scotland and Ireland. 
In Nov 1875 William Holman Hunt (age 48) and Marion Edith Waugh (age 28) were married at Neuchâtel, Switzerland since marrying your late wife's sister was illegal in England - see 1835 Marriage Act. She his first wife's younger sister contrary to English Law; an example of Married to Two Siblings. His brother-in-law Thomas Woolner (age 49) considered the marriage immoral; they never spoke again.
