How did Bayer name the brightest star in the constelation?

Bayer named the brightest star in a constellation using a Greek letter system, typically designating it with the letter "alpha" followed by the name of the constellation. For example, the brightest star in the constellation Orion is called Alpha Orionis, commonly known as Betelgeuse. This system, established by Johann Bayer in his 1603 star atlas, ranks stars based on their brightness relative to others in the same constellation.