There is nothing quite like a royal wedding, is there? The pomp and ceremony are surely enough to bring a tear to even the most cynical of eyes. A royal marriage, on the other hand, is a different beast altogether. And we are witness to quite an extraordinary historical shift in royal marriages – we are now seeing royals marry because they actually like each other.

For thousands of years, love had very little to do with royalty marrying. When the monarchy held absolute power over a nation, a marriage was more of a business arrangement than any kind of act of personal devotion. A marriage could secure alliances with foreign powers, replenish the royal coffers, and, of course, secure the dynasty by supplying legitimate offspring. Whether or not the bride and groom actually liked each other was neither here nor there.

But that didn’t mean the king and queen were expected to live loveless lives, far from it. So, what was the secret to a royal marriage? The answer to that is sex, with as many different people as possible – for the king, at least. This situation created one of the most important and coveted positions in the Royal Court, the royal mistress. It was the mistress who was expected to tend to the king’s romantic and sexual needs. The queen was expected to produce children, support the king, and patronise the arts, if she had the time.

Whereas today, any royal infidelities would be conducted (hopefully) with some discretion, the royal mistress was once an official position at court, and a highly competitive one at that. Agnès Sorel (1422-50) was the first woman to be officially recognised as the royal mistress of France in 1444. She was often painted with one boob out, leading some to suggest this was the fashion at the time. The jury is still out on that one, but she was certainly was the lover of King Charles VII and his decision to elevate her to the status of maîtresse-en-titre, and create a new role for women at court, forever changed what was expected in a royal marriage.

The practice was soon adopted throughout the royal courts of Europe and quickly became an expected, even fashionable custom. So much so that Frederick I of Prussia (1657-1713) appointed Catharina von Wartenberg (1674-1734) as his official mistress, but they never actually had sex. By all accounts, Frederick really did love his wife but was concerned his sexual prowess would be questioned if he didn’t also keep a mistress. So, Catharina got the money and the titles, and was required to play along and regularly appear in public as the royal mistress, but never had to kick up her heels in service of the King. Nice work if you can get it.