In the early 20th century, Reza Shah Pahlavi came to power, and he was all about modernizing the country. He wanted to get rid of the old, traditional ways and bring in the new, and that included changing the country's name. So, in 1935, he officially declared that Persia would from then on be known as Iran.
But, why Iran, you ask? Well, it's actually pretty simple. Iran is the Persian word for "land of the Aryans," and it was a name that had been used internally for centuries. So, in a way, it was like the country was just upgrading its brand, you know, like when your favorite coffee shop changes its name to something cooler.
Now, you might be wondering, what about all the other countries that used to be known by different names? Like, Siam becoming Thailand, or Ceylon becoming Sri Lanka. It's like, what's in a name, right? But, for Iran, the name change was a big deal, and it marked the beginning of a new era for the country.