Languages are a funny thing. Among all the rules of grammar, syntax, and spelling, there are also regional dialects, vernaculars, and colloquialisms that can sometimes make understanding your native language (never mind a foreign one) difficult at times. The truth is we use slang terms and colloquial idioms every day and don’t even know were doing it.

For instance, take the phrase “sacred cow.”

If you are a native English speaker, or fluent in English, you’ve certainly heard this phrase and probably used it yourself, hopefully correctly! The term “sacred cow” is often used in the context of government and politics. For example, in America the Social Security system is often referred to as a “sacred cow” that neither the Democrats nor the Republicans will touch. In Britain, the National Healthcare System is also often referred to as a “sacred cow.” You can probably gather from the context that the term refers to something (often a governmental institution or program) that, for whatever reasons, cannot be modified, altered, or cut.

You’re probably thinking: “Fair enough, but what’s all that have to do with a cow?”

It is difficult to say for sure when the phrase “sacred cow” entered the English language, but it was probably either in the late 1700s or early 1800s in England.

India was a collection of kingdoms when the British East India Company began setting up bases throughout the country in the 1600s. The British East India Company was subsidized by the British government and so the British military worked alongside company merchants to establish control of the country. After the Sepoy, or Indian Rebellion of 1857, control over India passed officially to the British crown. By that point, the connections between the countries were extensive and thousands of British citizens had lived in India and brought back tales of the country’s unique religious beliefs.

One of those was the Hindu belief that cows are sacred animals.

Pious Hindus abstain from eating beef and will do whatever they can to avoid hurting a cow, which is why whenever you see a news report, film, or television show from India, there’s always almost at least one cow running around in traffic.

So, the phrase probably first saw usage in England before making its way over to the United States and other English-speaking countries in the 1800s.

Another theory is that an Indian living in Janesville, Wisconsin sent a letter home to India in 1854 that was published in The Calcutta Times. In the letter, the pious Hindu Wady Jahed wrote about some of the curious customs of his American hosts, particularly how they ate the flesh of the sacred cow. He closed his letter with “Kiss the Sacred Cow for Me.”

It’s funny how some things make it into the English language.