Capitalization is part of writing the proper script of a language. In general the first word of a sentence, and all proper nouns are supposed to be capitalized. Did you ever wonder how capitalization became part of languages?
To solve this mystery, we need to analyze an old Roman script, called “uncial”. The Latin and Greek scribes of the 3rd century AD used Uncial, which is a majuscule (“large” or “capital” letter) script. The original 21 letters of the English alphabet were derived from the uncial style of writing. Gradually, as the language evolved, more letters were added, and the English language alphabet count increased from 21 to 26.
That means that the original script for English was all uppercase letters – then how did lowercase join the club? With time, a small, more rounded, and connecting style lettering was introduced. By the 9th century AD, the use of this minuscule lettering had become quite common. In fact, people started mixing the majuscule and minuscule lettering, the former used to stress and emphasize certain words. To formalize things, Modern English rules define that all proper nouns, and the first word of the sentence be capitalized!