It' not a matter of english. it sn't english, but latin, since the latin civilisatoion is the foudation of all the western civiliation. He is called like this because many chinese sounds don't existe in latin and we cannot pronounce them. besides we don't have tones.

In latin, all the names must end with US. Ending the name of someone, especially a foreigner with US, is a sign of respect and reputation. It show how great he was. All the intelectus and famous people of the past have a latin name.


Kong zi (cong fu zi) is called Confucius

and Meng zi  孟子 is called Mencius

Nota Bene : The letter K doesn't exxist in latin, so what the K used in pinyin is C in latin 

For some odd reason, we Latinized the name when his writings were first translated from Chinese. Maybe it was the cool thing to do back then - make him sound Roman, along with the other Classical writers? So anyway, the new version stuck. The same thing happend to 孟子 - Mencius.

Now I think of it, the same thing happened to the ancient Greek writers too...

From 孔夫子