Original: Principia Mathematica (Stanford Encyclopedia of Philosophy) Gödel is best known for his two incompleteness theorems, published in 1931 when he was 25 years of age, one year after finishing his doctorate at the University of Vienna.
Simplified: Fame Gödel is best known for his two incompleteness theorems. He was 25 years of age, and had just finished his doctorate at the University of Vienna one year earlier.