Photo provided by Arthur Hardy -- Illustration from Frank Leslie's Illustrated Newspaper March 22, 1879 showing the Rex delegation disembarking the Robert E. Lee on the day before Fat Tuesday.

The popular Lundi Gras celebration on the riverfront began in 1987, organized around the river arrival of the king of Carnival at Spanish Plaza on the eve of Mardi Gras.

This new tradition, with roots in the late 1800s, was the brainchild of New Orleans Magazine editor Errol Laborde. The partnership among the city, private business (the Rouse Co.’s Riverwalk shopping mall) and the Rex organization was an instant success.

The historic Krewe of Proteus joined the activities by rerouting its parade to travel down Poydras Street near the riverfront. Soon, musical entertainment and a fireworks display were added.

As the event grew, the Zulu Social Aid & Pleasure Club joined in and staged its own river arrival for its monarchs. Zulu’s all-day Golden Nugget Festival at the adjacent Woldenberg Park started in 1993.

Until 2015, Rex arrived at Spanish Plaza aboard a Coast Guard cutter. Last year, Rex arrived on a vintage train, and he will do so again this year.

The evening includes a meeting of the Rex and Zulu royalty with the mayor, as the final countdown to Fat Tuesday is launched.

The original Monday arrival of Rex on the river dates to 1874, when the king of Carnival added a new feature to the city’s celebration during his third year in existence.

In his 2010 book “Rex, An Illustrated History of the School of Design,” Dr. Stephen Hales, the organization’s historian, writes: “The Monday before Mardi Gras became a celebration unto itself, a festive prelude to Tuesday’s centerpiece. Crowds gathered to greet the Monarch as he stepped from the gangplank of his festive Royal Yacht or emerged from his Royal Train. The Monday King, usually a disguised stand-in for the Rex who would reign on Tuesday, arrived in the company of a formally dressed delegation of Rex leaders and costumed guards.”

A 1915 guidebook described the scene as follows: “Thousands lined the levees to watch Rex make his journey to the city by way of the river … accompanied by tugs and merchant steamers. The arrival of the gaily decorated flotilla, amid the booming of cannon and the loud sounds of music … should not be missed.”

Famous vessels such as the legendary steamship Robert E. Lee served as the royal yacht.

The Monday king, usually made up to resemble a distinguished character such as Louis XIV, Charles II or Charlemagne, was transported in a special carriage or float as he led a parade of military units and bands to City Hall, where the mayor presented him with the keys to the city.

When Carnival returned after World War I in 1920, the Monday celebration did not.

For the centennial of Rex in 1971, the organization staged a one-time arrival by boat. But the tradition would not become an annual rite again for another 16 years.