View pictures in App save up to 80% data.

No article of clothing has become quite as synonymous with the royal family in recent years as stylish headwear. Since the 1950s, ostentatious hats have been something of a staple in the British monarchy's wardrobe, particularly among the women, who have sported all manner of eye-catching head coverings from large showstoppers to more functional pieces, like those worn by the late Queen Elizabeth II. Given the popularity of this cranial accoutrement, you'd be forgiven for not noticing that the royals are seldom ever caught wearing their hats after dark. 

Speaking with Reader's Digest, etiquette coach Laura Windsor explained that the royal family adheres to a strict dress code that states hats cannot be worn after 6 p.m. According to Diana Mather of The English Manner etiquette consultancy, the reason for this specific time is simple, as she told BBC: "[6 p.m.] is when the ladies changed into evening dress, and tiaras and the family jewels would come out." Grant Harrold, former butler to King Charles III, added that wearing tiaras instead of hats also showed a woman's societal standing and relationship status, as only married women wore tiaras. "For the gentleman, it was a clear sign not to make advances toward the lady in question," he said.

While tiaras are now rarely seen, typically reserved for white-tie occasions and formal responsibilities, the tradition of wearing hats continues to be an integral part of the royal dress code.

View pictures in App save up to 80% data.

The guidelines for headwear in the royal dress code extend beyond just the appropriate times for donning a hat. As noted by Laura Windsor, there are specific rules regarding the type of hat that members of the royal family may wear, which vary by season and event. During the spring and summer months, straw hats are encouraged, while felt hats are more suitable for the fall and winter seasons. For occasions such as weddings and funerals, it is recommended that hats have shorter brims to prevent obstructing the view of other attendees. Additionally, there are strict protocols on how royals should wear their hats; proper etiquette dictates that hats should be pinned securely to the head, and they should not be held in hand unless the situation specifically requires it.

The royal dress code also has guidelines regarding which hats are to be worn depending on the style of the outfit. Speaking with Woman & Home (via Bustle), etiquette expert Lisa Forde explained that "if an A-Line skirt is selected, it is important to ensure that the hat's brim width balances out the volume of the skirt. If the outfit is very tailored, a more simple hat will be selected." 

Royal commentator Richard Fitzwilliams explained that the fundamental rule of the royal dress code is to ensure that members of the royal family are always attired appropriately for any given event. Although the stringent regulations surrounding headwear might appear unreasonable to outsiders, they play a crucial role in maintaining this principle.