For the British Royal Family, marrying within the country, has been a relatively rare phenomenon until modern times.

The expectation was that members would marry other royals, of which there would be a limited supply outside of the limitations of consanguinity.

So, especially for royal males, it was necessary to look abroad for royal brides.

In time that choice became limited to countries that were Protestant, especially after 1688 and that meant Germany, with its many states and princedoms became the prime supplier. In that respect, Queen Alexandra (a Dane) was an exception.

Those who were down the Line of Succession often could marry within the country but even then it had to be to aristocrats.

Many, though technically German with German names titles and ancestry were born and raised in the UK.

When he married a member of the Scottish nobility (though she was actually born in England), the Queen's father did not expect to become King.

Yes a fascinating subject to read up on JockInSkye!