[nicollo]

The Brits used primogeniture to resolve the problem of inheritance, but even with, or maybe because of, the priesthood or military for the second sons, it caused intrigue and adventurism. Much colonial history was made by second sons.

Tocqueville credited the end of primogeniture and entail (insoluble estates) for the spread of democracy in the US:

"The law of equal inheritance, by giving an equal portion of the father's property to all the children, compels the rich to divide their estates among their children; and forbids the poor to divide theirs at all. It takes wealth from some, and poverty from none; it secures every man's independence without increasing anyone's power, and without disturbing the balance of society. Democracy favors the division of estates for another reason; not only does it make the poor equal to the rich, but it places a greater number of citizens above the level of poverty, and it infuses comfort and independence into a multitude of families."

(Volume 1, Part 2, Chapter 4)

[SunkenCiv]

Same went for the Hessians, which led to younger sons going into mercenary work. Quite a number were shipped to the 13 colonies by George III to kill the American revolution.

The famous battle of Trenton and its follow-up led to hundreds of Hessian POWs, who were marched off into Pennsylvania Dutch (Deutsch) country where they'd be stranded among other German speakers and put to work there.

They looked at their situation, and had a few years to think about it, and a good number of Hessians (both the POWs and others) saw they'd have a much better deal here, and stayed. Rob Lowe's episode of "Who Do You Think You Are?" uncovered his Hessian ancestor.

For that matter, during the medieval warming period the Scandinavian population blew up pretty well and a similar lack of inheritable land led to the Viking expansion into eastern Europe, the British Isles, Normandy, Sicily, Iceland, Greenland, and (for a 100-150 years) North America.