To meet one's waterloo, is a phrase based on the major battle that took place at Waterloo in present day Belgium in Sunday June 15, 1815. The battle led to Napoleon's, France's famous historical leader, major defeat. Napoleon was defeat by a coalition of British, Dutch, and Prussian forces at this battle. It is viewed as a major battle and a crushing defeat for Napoleon. So "to meet one's waterloo" is to face a pivotal moment of defeat.
