Article. General notion

1.3.1.1 The History of the French Definite Article
Speaking about the French definite article one should know that it was a roman innovation. It came from Latin ille(masculine) and illa(feminine) which served as adjectives and demonstrative pronouns as well. In ancient France only the proclitic form of them was preserved that lost early their first syllable and became unstressed.
(il)li>li − Nominative case, masculine, singular
(il)lu(m)>lo was used till the end of the XIth c. and then deafened in le − Objective case, masculine, singular
illī>li, illos>los soon was replaced by les − masculine, plural;
illa>la − feminine, singular;
illas>les − feminine, plural.
The French definite article retains a long time the demonstrative and the determinative meanings:
e.g.: Tresqu’en la mer cunquist la tere altaigne. (Rol.,3)
Jusqu'а la mer il conquist la terre hautaine.
He conquered the lordly land till the sea.
This is an example of the French article’s agreement with the noun in gender, number and case; at the same time the article determines the noun being used as ancient demonstrative: “la mer” means “this sea”= ‘the sea’.
So, we notice that the development of the French language was influenced by Latin which already had some notions of gender, number and case. It should be mentioned that from the previous times the French definite article had the forms of masculine and feminine. It had differentiations between singular and plural forms. Apparently the French article had the same meaning of a demonstrative.
Since English and French are two languages from different linguistic families they were developed differently. The articles have different origins. That is why there are many differences in their characteristics.
Nevertheless, both, the English definite article and the French definite article, take their origin from the demonstrative pronoun retaining the demonstrative meaning till nowadays.

1.3.1.2 Article йlidй
One of the forms of the definite article in French is used with the apostrophe (l’) and has its own name article йlidй (fused article). It is used only with nouns that begin with a vowel or mute h in singular. The definite articles le, la lose their vowels in such cases and take the apostrophe – l’, e.g. l’arbre, l’иre, l’homme, l’habitude.