Catholics Wear Green on St. Patrick's Day

Protestants are supposed to wear orange on St. Patrick's Day because you're not Catholic, just FYI. Protestants wear orange because of William of orange, the Protestant king who overthrew the Roman Catholic King James II in the glorious revolution. So this is a sign of goodwill towards your Catholic brothers and sisters. We're just going to rock the green. Let's all just come to the same page. I don't even totally clear on the story of St. Patrick himself. Does anyone know?