Arcturus wasn't "discovered" in the sense of being found for the first time. It's one of the brightest stars in the night sky and has been known since ancient times.

Here's what we do know:

* Ancient observations: Arcturus was recorded by ancient civilizations like the Babylonians, Egyptians, and Greeks. It's even mentioned in the Bible!

* Early star catalogs: Arcturus appears in early star catalogs, like the one created by the Greek astronomer Ptolemy in the 2nd century AD.

Therefore, it's impossible to pinpoint a specific date for the "discovery" of Arcturus. It has been recognized and observed by humans for thousands of years.