Which of these countries was formerly known as Ceylon?

The Horror, I spent a lovely day there on my way to Australia in 1960 My dad and I visited a beautiful Buddhist Temple, the guide gave me a frangipani flower. My dad showed me how to "press" it and I still have it, 65 years later.

DrO, The first sentence in the description says and I quote "Formerly known as Ceylon"

DrO, Doesn’t explain when or why it became Sri Lanka.

Description does not mention it formerly being called Ceylon or when it changed to its current name to Sri Lanka.

Beautiful place and the Sri Lankans are so friendly