What Meghan Markle tells us about the modern British monarchy

But that fact that the fifth in line to the British throne and grandson of Queen Elizabeth II is marrying an outspoken American actress has served as a timely reminder of how far the most famous family in the world has come in five decades.

The freedom for high-profile members of the Royal Family to marry who they want -- rather than who they should -- has been a gradual process.

We only need look back two generations to the current monarch, Elizabeth II, and we see a young princess who married a Danish prince of German and Greek descent -- the romance at the center of Netflix's drama "The Crown."

In the immediate aftermath of World War II, it was controversial that a 21-year princess was marrying a man with family who had fought alongside the Germans. But the idea that she would marry a non-royal might have arguably been a more alien concept.

Thirty-four years later, when Elizabeth and Philip's eldest son Charles announced his engagement to Diana, things had moved on ever so slightly. Despite coming from an aristocratic background and a world where she regularly rubbed shoulders with royals, Diana had a distance from royalty that made her a fairytale bride in the eyes of the nation.

Leap forward to 2010, and Prince William -- the man who will one day be king -- announces his engagement to a woman he lived with while studying at university.

The Duchess of Cambridge, known then as Kate Middleton, though from a wealthy family, was a commoner. The development marked another leap forward into the modernization of this family and once again, a fairytale romance was embraced by the world's media.

So how significant is it that Prince Harry has proposed to his American, mixed-race girlfriend -- a public figure in her own right, due to her successful acting career and work as an activist?

Much is being made of the fact that Meghan Markle is mixed race, American and a divorcee. When discussing this earlier on CNN Talk, my colleague Ayesha Hazarika put it far better than I could: "The royal family are the absolute top of the British class system, it is the most elitist system on the planet ... a lot of people of color will think good: it's high time that this system was opened up a bit more."

What role is Markle likely to play in the family? She will now join the close-knit group of younger royals; Prince Harry, it must not be forgotten is Prince William's best friend and closest confidant. He is also very close to his sister-in-law -- as is evident from the fact that shortly after their marriage, Harry lived in William and Kate's apartment.

The three run mental health charity Heads Together -- a cause that clearly matters enormously to all of them. They have been almost universally praised for the sincerity with which they talk about it.

And while Meghan Markle has been moving away from her acting work and her philanthropic activism has taken a greater role, it is clear that she is a woman of conviction with strong opinions and passions.

Whereas the Duchess of Cambridge has followed the Queen's example by holding back on expressing any major opinions, it seems unlikely that Meghan will follow a similar path. And even less likely is that Harry -- a headstrong man himself -- would hold her back.