A popular catchphrase among modern-day drinkers is one you’ll recognize. You’ve probably said it yourself: “It’s five o’clock somewhere!”

A common assumption is that this phrase was inspired by American 9-to-5 workers’ clock-out time, marking the end of the traditional workday, and the beginning of another American invention — “happy hour.” In actuality, the origins of the phrase are unknown, although its regular use in our modern-day vernacular is due at least in part to Alan Jackson and Jimmy Buffett’s drinking anthem of the same name.

Across the pond, there exists a cheeky, albeit colonialist equivalent to “It’s five o’clock somewhere,” used to shake off judgement for day drinking, and to signal it’s time for a drink: “Commemorating the siege of Gibraltar.”

For the less geographically astute: Gibraltar is a British overseas territory, whose location at the southern tip of the Spanish peninsula made it highly desirable to military powers as a gateway to the Mediterranean Sea. Gibraltar was such an attractive territory, it endured 14 military sieges, stretching all the way back to 1309, when King Ferdinand IV of Castile captured the province from the Moors.

Nearly every century that followed produced another attack on Gibraltar — so many, in fact, that the island nation became the root of a casual excuse to drink.

In the book “Around the World in 80 Words,” author Paul Anthony Jones suggests that sailors from the British Navy of the time were the ones to begin toasting to the “Siege of Gibraltar.”

“In eighteenth-century naval slang, anyone who fancied a drink but could not think of a good enough excuse to have one — or, alternatively, anyone caught having a drink and questioned why they were on the booze at whatever time they were discovered — would reply that they were commemorating ‘the anniversary of the Siege of Gibraltar,’” Jones writes.

The expression stuck, taking on a somewhat comical inflection. Jones continues, “Given the sheer number of them in the military history books, it was fairly likely that regardless of the date, there was an anniversary of at least one siege of Gibraltar coming up sometime soon.”

What began as colonial occupation became a colloquial phrase. Much like our “five o’clock,” the toast recognizes that no matter what the clock says, it’s an acceptable time to start drinking, somewhere.

So the next time you’ve got a hankering for that midday Martini, be sure to pour one out for Gibraltar — before sharing a toast, and your impressive grasp of military history.