On this day, April 4

1865 President Abraham Lincoln, accompanied by his son Tad, visited the vanquished Confederate capital of Richmond, Va., where he was greeted by a crowd that included former slaves. 1968 Civil rights leader Martin Luther King Jr., 39, was shot and killed while standing on a balcony of the Lorraine Motel in Memphis, Tenn.; his slaying was followed by a wave of riots. James Earl Ray later pleaded guilty to assassinating King, then spent the rest of his life saying he’d been set up.

1978 Pittsburgh City Council overrode Mayor Richard Caliguiri’s veto of an anti-pornography referendum designed to provide a mandate for “cleaning up” Liberty Avenue and other pornography retail areas.

1991 Sen. John Heinz, R-Pa., and six other people, including two children, were killed when a helicopter collided with Heinz’s plane over a schoolyard in Merion, Montgomery County.

2009 Eric G. Kelly, Stephen J. Mayhle and Paul J. Sciullo II, three Pittsburgh police officers, were shot and killed outside a Stanton Heights home by suspect Richard Poplawski, who was waiting for them with an AK-47 and other firearms after his mother made a call to 911.

Today’s birthdays: Record company executive Clive Davis, 89. Author Kitty Kelley, 79. Actor Craig T. Nelson, 77. Actor Walter Charles, 76. Actor Christine Lahti, 71. Country singer Steve Gatlin (The Gatlin Brothers), 70. Writer-producer David E. Kelley, 65. Actor Constance Shulman, 63. Actor Phil Morris, 62. Actor Lorraine Toussaint, 61. Actor Hugo Weaving, 61. Rock musician Craig Adams (The Cult), 59. Talk show host/comic Graham Norton, 58. Actor David Cross, 57. Actor Robert Downey Jr., 56. Actor Barry Pepper, 51. Singer Jill Scott, 49. Rock musician Magnus Sveningsson (The Cardigans), 49. Magician David Blaine, 48. Singer Kelly Price, 48. R&B singer Andre Dalyrimple (Soul For Real), 47. Country musician Josh McSwain (Parmalee), 46. Actor James Roday Rodriguez, 45. Actor Natasha Lyonne, 42. Actor Eric Andre, 38, Actor Amanda Righetti, 38.

Thought for today: “The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy.”

— Martin Luther King Jr. (1929-1968)