The origin of Legendre's Polynomials

Once upon a 'real space' existed an army of 'polynomials' who always lived in the 'domain' of [-1,1]. This brave and strong army won many territories. Many 'differential equations' bowed to them and accepted them as their 'general solution'. They were 'normalized' and had a heavy 'weight factor'. Even though they fought so many battles, they surprisingly remained quite 'complete'. So to honor these great class of polynomials, one great historian gave them the title "Legendary Polynomials".

(In case you didn't get the joke: Legendre's polynomials are named after Adrien-Marie Legendre. They occur very often in maths and physics problems. They form a linear vector space which is characterized in terms of 'domain', 'normalization', 'weight factor', 'completeness')