Also in the minds of the founders of Rex was the desire to lure tourism and business to New Orleans in the years after the American Civil War.

[2] This was adopted because the Grand Duke Alexis of Russia had a fondness for Lydia Thompson, the actress who sang the song in the musical, which was playing in New Orleans at the time of the first Rex parade in 1872.

In effect, the ordinance required these, and other, private social groups to abandon their traditional code of secrecy and identify their members for the city's Human Relations Commission.

The Rex organization and the Mistick Krewe of Comus still hold their annual balls together on Mardi Gras night.

Unlike some other old-line krewes, Rex's route never went through the French Quarter prior to the city's ban on parades in the Vieux Carre which took effect in 1973.

In addition to its famous parade, the Rex Organization also holds a private ball for its membership and invited guests on Mardi Gras night.

This event is televised live locally (and to selected areas outside of the city) – and many New Orleanians stay up to watch despite their weariness – until the very end.

By proclamation from Rex usage of a live ox "was not in harmony with the beautiful displays which are produced in this era and (it) must be relegated to the past."

Today le boeuf gras is the fourth float in the Rex parade and is surrounded by masked krewemen costumed as butchers and bakers, many of whom are past kings of Carnival.

The Rex motto, "Pro Bono Publico" (for the public good)[8] was adopted during this time, and continues to define the organization's commitment to service.

Following Hurricane Katrina, Rex organized a series of community service initiatives in 2006 under the banner "Operation Pro Bono Publico."