* Historical Influence: English evolved from various dialects, including Old English, which had the "u" in "colour." American English, however, developed separately and favored simpler spellings.
* Noah Webster: Noah Webster, the American lexicographer, actively promoted simplified spellings in his dictionary, published in 1828. He believed that spelling should reflect pronunciation and be easier to learn.
* British English: British English, however, retained the "u" in "colour," reflecting the influence of older English.
So, while both "color" and "colour" are correct spellings, they are simply conventions used in different English-speaking regions.