HeY ! HeY ! I Am SUCH A gReAt PErSON ! WHeN WAs I BORn ?
AlSO, WHAt IS mY NAmE, sTaCK USEr ?
The answer is
If you ignore all spaces but very much mind the case, the riddle is a concatenation of symbols for chemical elements: for example, "A gReAt" gives you silver (Ag), Rhenium (Re) and Astatine (At). If you sum all the atomic numbers of said elements, you get 1834, which is the birth year of Mendeleev. With the chemical content of the riddle, there is few room for doubt that he's the solution (although it's probable he was not the only Human born that year).