The Royal Family...
As they always say, you can choose your friends, but not your family.
This applies for the Royal Family as well, I could imagine. In every family, you have a black sheep, someone, whom you´d prefer not to see at gatherings, but you have no choice.
I don´t know who of the following members of the Royal Family belongs to this category, (just have some ideas), but anyway, in this section, you can find some of the members of the Royal Family who did not become King or Queen, but still belong to the "Royal Company".
The first one, I admit it, may seem a bit far-fetched. It´s Robert
Cary (1560-1639, the 1st Earl of Monmouth later),
who´s related to Queen Elizabeth I. His
grandmother (Mary Boleyn) and Queen Elizabeth´s mother, Anne Boleyn
(second wife of King Henry VIII, she was beheaded in 1536), were sisters.
There is no direct connection (maybe he´s a kind of "cousin") between
Cary and Queen Elizabeth, but he spent much time at her court and was present
when she died in 1603. He rode to Edinburgh immediately (in two days!) to
inform Scottish King James VI of her passing, which meant that King James
was King of England as well, the "United Kingdom" from then on.
My small selection continues with a few of the sons of King George III. Two of them became King themselves (King George IV and King William IV), the other ones died too young or were "out-throned" by Queen Victoria.
Her father was Prince Edward, the Duke of Kent (1767-1820). Edward
was the fourth
son of King George III, but had he lived, he would
have become King after his brother William died in 1837. His other brothers
didn´t produce surviving male heirs as well, so his daughter Victoria
became Queen. Edward died when his daughter was less than a year
old.
Another son (the sixth) of King George III was August Frederick, Duke
of
Sussex
(1773-1843). He married twice,
but his wives weren´t up to "Royal standards", and they didn´t
have children, anyway.
The seventh son of King George III was Adolph Frederick, the Duke of
Cambridge (1774-1850).
Like his brothers, he led a, hm, independent life
and did only marry after the parliament "asked" him and his brothers to marry
propperly and produce heirs (in 1817, the only existing heiress had died,
Princess Charlotte, the only child of Prince-Regent George).
The next entry in this section is Prince George, the Duke
of Kent (1900-42), the fourth son of King
George V. His two older brothers had become King Edward VIII, and, after
his abdication, King George VI. The Duke of Kent, the first member of the
Royal family who worked in public service, died in Scotland in a plane-crash.
His son is Edward, the Duke of Kent (*1935),
grandson of King George V, cousin of the current
Queen Elizabeth II. The Duke of Kent, among other things, can be seen at
the tennis-tournament in Wimbledon each year, when he and his wife give out
the trophies to the champions.
Someone who might change the category on my site one day is Charles, Prince
of Wales (*1948). Styled Duke of Cornwall (among many other titles) after
his birth at Buckingham Palace, he became heir to the crown when his mother
ascended to the
throne in 1952 after her father´s passing.
In 1958, he was officially made Prince of Wales, traditionally the title
of the #1 behind the Queen or King. He studied at several universities, among
them the university of Wales, where he became the first Royal to learn the
Welsh language in a long time (if at all). After a military career, he became
a significant figure in British agriculture, culture and architecture. His
first marriage to Lady Diana Spencer (1961-97) in 1981 ended in
divorce (1996), the second to long-time friend Camilla Parker-Bowles
(created Duchess of Cornwall) in 2005 will last longer, it seems.