Everyone who knows even a little bit of English should know that the article 'a' is used before words that do not start with a vowel.
For example: a loaf of bread.
However, when the word starts with a vowel (a, e, i, o or u), the article 'a' becomes 'an'.
For example: an apple.
Simple, is it not?
Well, no. English can never be this simple. There are always exceptions to the rules. Always.
So for words that do start with a vowel but somehow pronounced like they start with a consonant(letters which are not vowels) , the article used is 'a'.
For example: a uniform
Because uniform is pronounced you-nee-form.
How about words that start with a consonant, but the consonant is silent? Like that of the word 'hour'.
In this case, we use 'an' instead of 'a'.
For example: an hour.
So these are the rules and exceptions that determine the usage of a and an in English.
If I were to ask you, which article would you use for the word 'history'?
According to what we just learnt, it should be 'a', right? As in, 'a history'.
But why, oh why do we still see people use 'an history' in writings?
I am aware of the fact that people used to write it that way. The keywords here are 'used to'. Not 'we still do' but 'used to'. When old people write 'an history', I am probably okay with that but when people who are just as young as I am write 'an history', that is just being pretentious.