Columbus Day is a U.S. holiday that commemorates the landing of Christopher Columbus in the Americas on October 12, 1492. It was unofficially celebrated in a number of cities and states as early as the 18th century, but did not become a federal holiday until 1937. For many, the holiday is a way of both honoring Columbus’ achievements and celebrating Italian-American heritage. But throughout its history, Columbus Day and the man who inspired it have generated controversy, and many alternatives to the holiday have proposed since the 1970s.

Christopher Columbus was an Italian-born explorer who set sail in August 1492, bound for Asia with backing from the Spanish monarchs King Ferdinand and Queen Isabella.

Columbus intended to chart a western sea route to China, India and the fabled gold and spice islands of Asia. Instead, he landed in the Bahamas, becoming the first European to explore the Americas since the Vikings established colonies in Greenland and Newfoundland during the 10th century.

Later that October, Columbus sighted Cuba and believed it was mainland China; in December the expedition found Hispaniola, which he thought might be Japan. There, he established Spain’s first colony in the Americas with 39 of his men.

In March 1493, Columbus returned to Spain in triumph, bearing gold, spices and “Indian” captives. The explorer crossed the Atlantic several more times before his death in 1506.

It wasn’t until his third journey that Columbus finally realized he hadn’t reached Asia but instead had stumbled upon a continent previously unknown to Europeans.

The first Columbus Day celebration took place in 1792, when New York’s Columbian Order—better known as Tammany Hall—held an event to commemorate the historic landing’s 300th anniversary. Taking pride in Columbus’ birthplace and faith, Italian and Catholic communities in various parts of the country began organizing annual religious ceremonies and parades in his honor.

In 1892, President Benjamin Harrison issued a proclamation encouraging Americans to mark the 400th anniversary of Columbus’ voyage with patriotic festivities, writing, “On that day let the people, so far as possible, cease from toil and devote themselves to such exercises as may best express honor to the discoverer and their appreciation of the great achievements of the four completed centuries of American life.”

In 1937, President Franklin D. Roosevelt proclaimed Columbus Day a national holiday, largely as a result of intense lobbying by the Knights of Columbus, an influential Catholic fraternal organization.

Controversy over Columbus Day dates back to the 19th century, when anti-immigrant groups in the United States rejected the holiday because of its association with Catholicism.

In recent decades, Native Americans and other groups have protested the celebration of an event that resulted in the colonization of the Americas, the beginnings of the transatlantic slave trade and the deaths of millions from murder and disease.

European settlers brought a host of infectious diseases, including smallpox and influenza, that decimated indigenous populations. Warfare between Native Americans and European colonists claimed many lives as well.

The image of Christopher Columbus as an intrepid hero has also been called into question. Upon arriving in the Bahamas, the explorer and his men forced the native peoples they found there into slavery. Later, while serving as the governor of Hispaniola, he allegedly imposed barbaric forms of punishment, including torture.

In many Latin American nations, the anniversary of Columbus’ landing has traditionally been observed as the Dìa de la Raza (“Day of the Race”), a celebration of Hispanic culture’s diverse roots. In 2002, Venezuela renamed the holiday Dìa de la Resistencia Indìgena (“Day of Indigenous Resistance”) to recognize native peoples and their experience.

Several U.S. cities and states have replaced Columbus Day with alternative days of remembrance. Alaska, Hawaii, Oregon and South Dakota have officially replaced Columbus Day with Indigenous Peoples Day, as have cities like Denver, Phoenix and Los Angeles.

Columbus Day was originally observed every October 12, but was changed to the second Monday in October beginning in 1971.

In some parts of the United States, Columbus Day has evolved into a celebration of Italian-American heritage. Local groups host parades and street fairs featuring colorful costumes, music and Italian food. In places that use the day to honor indigenous peoples, activities include pow-wows, traditional dance events and lessons about Native American culture.