JACKSON - Freedom Riders coming to Mississippi this spring to mark the 50th anniversary of their challenge to the South's brutal system of segregation "will find Mississippi an enormously changed state as to race relations," Gov. Haley Barbour said Monday.

Barbour, a potential 2012 presidential candidate, spoke during a Martin Luther King Jr. holiday gathering in Jackson sponsored by Millsaps College and Tougaloo College, which was a hub of activity during the civil rights movement.

"A lot of reprehensible things took place between the advent of the Freedom Rides in 1961 and enactment of the Civil Rights Act of 1964, the Voting Rights Act of 1965 and finally integration in the bulk of this state's public schools," Barbour said in remarks prepared for delivery at the shared event at Millsaps. "Deplorable actions including the murder of innocent people, young men in service to a cause that was right, will always be a stain on our history.

"And school integration did not put an end to racial problems or prejudice," Barbour said. "However, the 100-plus Freedom Riders participating in the 2011 celebration will find Mississippi an enormously changed state as to race relations."

The Freedom Riders were young people, black and white, who rode buses together into Mississippi and other states in the South to challenge the segregated society in 1961. Some were tossed into prisons in Mississippi, suffering in the un-air-conditioned quarters in the summer.

Starting May 22, Mississippi is hosting several events to commemorate their work. Barbour will host a reception at the Governor's Mansion.

Mississippi marked Monday as a dual holiday honoring King and Robert E. Lee, commanding general of the Confederate army during the Civil War. At the request of Democratic Sen. Hillman Frazier of Jackson, who is black, the Mississippi Senate adjourned Monday in memory of both King and Lee.