weierstrass was a very influential teacher, and his meticulosly prepared lectures established an ideal for many future mathematicians; " Weierstrassian rigor" became synonymous with " extremely careful reasoning" Weierstrass was " the mathematical conscience par excellence," and he became known as "the father of modern analysis" He died in 1897 , just one hundred years after the first publication, in 1797 by Lagrange, of an attempt to rigorize the calculus.