Photo: Linda Broström, The Royal Court of Sweden

Why does King Carl Gustaf of Sweden have the number 16 Roman numerals in between his two names?

King Carl XVI Gustaf means that the current monarch is the 16th ruler to use the name Carl (or Charles).

However, there haven’t actually been 16 monarchs to use the name throughout Sweden’s history.

The first trace of the use of Carl/Charles goes back to 1161, when Carl VII reigned. The Roman numerals were not given to his name until after his death, and the reason he was listed as VII instead of I was based on a fictional history of Sweden that was used by King Charles IX (who was on the throne from 1604 to 1611).

A historian named Johannes Magnus wrote the unreliable Historia de omnibus Gothorum Sueonumque regibus (History of all Kings of Goths and Swedes) during the 16th century and was said to have made up the first six Carl/Charles monarchs – leading to how Carl VII became just that, the seventh King Carl/Charles.

Since then, Swedish monarchs named Carl/Charles have added the Roman numerals in order up until the country’s current King, Carl XVI Gustaf.

If the laws of succession hadn’t changed, Carl Gustaf’s son, Carl Philip, would be the next Carl to ascend the throne, but a change in the succession laws in 1980 meant that the former Crown Prince was replaced by his elder sister, Victoria, as heir to the throne.