The and that are common developments from the same Old English system. Old English had a definite article se (in the masculine gender), sēo (feminine), and þæt (neuter). In Middle English, these had all merged into þe, the ancestor of the Modern English word the.
Where did the word it come from?
Old English hit, neuter nominative and accusative of third person singular pronoun, from Proto-Germanic demonstrative base *khi- (source also of Old Frisian hit, Dutch het, Gothic hita "it"), from PIE *ko- "this" (see he).
Why do we have the word the?
The word the is very important to native speakers of English because it is used to divide the world we process through language into two categories: old information and new information. It helps us to divide the world into things which we agree are known, or important, and things which we feel aren't.
What is the oldest word?
Mother, bark and spit are some of the oldest known words, say researchers. Continue reading → Mother, bark and spit are just three of 23 words that researchers believe date back 15,000 years, making them the oldest known words.
Do we need the word the?
Here's another way to explain it: The is used to refer to a specific or particular member of a group. For example, "I just saw the most popular movie of the year." There are many movies, but only one particular movie is the most popular. Therefore, we use the.