Good morning

does anyone out there know were this saying came from orig. never thought about it untill now but does not sound good.

"How do you do? (literally "how is your health?), good morning, good afternoon, and good evening have been English greetings since the mid 15th century." From I Hear America Talking: An Illustrated History of American Words and Phrases by Stuart Berg Flexner (Von Nostrand Reinhold Co., New York, 1976).