Meaning of 之 in this sentence?

Question

Why is 之 used in this sentence? 忍耐是幸福之门的一把钥匙. Cant it just as easily be substituted with 的? Please help me understand. Thanks.

Answer 1

Both Yuan C. and Yiran X. are correct, but the reason 之 is more elegant, more formal is because it comes from Classical Chinese, China's traditional literary language. Grammatically, the function of 之 in this sentence is exactly the same as 的 （though 之 also has other uses).

Answer 2

"之" is frequently used in proverbs and ancient Chinese, thus having a more "intellectual" sound to it. Also, because there is already a "的" in the sentence, using "的" again would just seem repetitive. Hope it helps!

Answer 3

之means的 in this sentence, it just make the sentence more academic and beautiful .only use for writing ,we never say that in real life.