A crusader is someone who actively supports or fights for a cause, often with great enthusiasm and dedication. The term originated from the historical Crusades, which were military campaigns launched by European Christians to regain control of the Holy Land from Muslim forces in the 11th-13th centuries. Those who took part in these wars were known as crusaders, fighting for their religious beliefs and a sense of duty. Today, the term is often used more broadly to describe anyone who passionately advocates or fights for a cause they believe in, whether it be political, social, environmental, or personal.