Oh I am sure a lot of those marriages were the common law type. Recognized by most states. Here is a list of states and the year in which common law marriages ceased to be recognized:
Common-law marriages can no longer be contracted in the following states, as of the dates given: Alaska (1917), Arizona (1913), California (1895), Florida (1968), Georgia (1997), Hawaii (1920), Idaho (1996), Illinois (1905), Indiana (1958), Kentucky (1852), Maine (1652, when it became part of Massachusetts; then a state, 1820), Massachusetts (1646), Michigan (1957), Minnesota (1941), Mississippi (1956), Missouri (1921), Nebraska (1923), Nevada (1943), New Mexico (1860), New Jersey (1939), New York (1933, also 1902–1908), North Dakota (1890), Ohio (1991), Oklahoma (Nov. 2010), Pennsylvania (2005), South Dakota (1959), and Wisconsin (1917).
As for the rest of the world, French-Vietnamese marriages were very common, Alexander the Great had wives from Babylonia to Afghanistan to India. Since he was the government in the areas he conquered, I am sure he recognized his own marriages.