The House of Orange-Nassau was one of the most influential royal houses in Europe in the 16th and 17th centuries. It originated in 1163 the tiny Principality of Orange, a feudal state of 108 square miles north of Avignon in southern France. The Principality of Orange took its name not from the fruit, but from a Roman-Celtic settlement on the site which was founded in 36 or 35 BC and was named Arausio, after a Celtic water god;^[10] however, the name may have been slightly altered, and the town associated with the colour, because it was on the route by which quantities of oranges were brought from southern ports such as Marseilles to northern France.

The family of the Prince of Orange eventually adopted the name and the colour orange. The colour came to be associated with Protestantism, due to participation by the House of Orange on theProtestant side in the French Wars of Religion. One member of the house, William I of Orange, organized the Dutch resistance against Spain, a war that lasted for eighty years, until the Netherlands won its independence. Another member, William III of Orange, became King of England in 1689, after the downfall of the Catholic James II.

Due to William III, orange became an important political colour in Britain and Europe. William was a Protestant, and as such he defended the Protestant minority of Ireland against the majority Roman Catholic population. As a result, the Protestants of Ireland were known as Orangemen. Orange eventually became one of the colours of the Irish flag, symbolizing the Protestant heritage.

When the Dutch settlers of South Africa rebelled against the British in the late 19th century, they organized what they called the Orange Free State. In the United States, the flag of the City of New Yorkhas an orange stripe, to remember the Dutch colonists who founded the city. William of Orange is also remembered as the founder of the College William & Mary, and Nassau County in New York is named after the House of Orange-Nassau