Dennis Heiner, a 72 year old Christian who was incensed by Chris Ofili's The Holy Virgin Mary, threw white paint accross the work and proceeded to smear the paint over the canvas.
The painting, part of the now infamous and appropriately named Sensation: Young British Artists from the Saatchi Collection, exhibition caused a great deal of controversy for using elephant dung and pornographic images in a picture of the Virgin Mary. It rallied christian groups to protest against the Brooklyn museum for showing the work.
Before the show opening 'Self-described artist Scott LoBaido was grabbed by police outside the Brooklyn Museum of Art for hurling fistfuls of horse manure at the museum's facade. `I'm expressing myself creatively!' shouted LoBaido, who criticized the upcoming exhibit as Catholic-bashing as police led him away.'This in turn prompted the museum to place it behind a protective plexiglass shield.
Heiner, a retired English teacher feigned sickness to lean against a wall without attracting the suspicion of a guard then ducked behind the plexiglass "'ook out a plastic bottle and squeezed white paint in a broad stroke across the face and body of the Madonna' He then smeared the paint over the head and bust of the painting, effectively obscuring the Virgin from view.
Heiner made no attempt to escape and when asked by one of the security staff "Why did you do it?It's blasphemous,' the man replied quietly." Heiner was later charged with second-degree criminal mischief and received a conditional discharge and a $250 fine which was viewed as extremely lenient by the arts community.
The work attracted the wrath of New York Mayor Rudolph Giuliani, who witheld the museums monthy funding and threatened eviction less they close the exhibition. The case went to court and Guilianni was forced to back down.
Ofili, is no stranger to outrage at his work. In 1998, Ray Hutchins, a 66-year-old artist from Staffordshire, protests Chris Ofili's winning of the Turner Prize by placing a large heap of manure on the steps of the Tate Gallery in London along with a sign, reading "Modern Art is a Load of Bullshit".
In a controversial move following the furore in New York, the National Gallery of Australia cancelled their planned hosting of the Sensation exhibition, "not because of moral outrage about the art" Dr Brian Kennedy, the gallery director said, "but for reasons of ethics." The ethical reasons alluded to were connected with the financing of the exhibition by "people with a direct commercial interest in the work of the artists." 
The fact that many major exhibitions are fincanced by companies with direct commercial interest in the work of the artists seemed to be lost on Dr. Kennedy as many in the art world and media criticised his resolve. Indeed, two years prior to the cancellation of Sensation another work offending the sensibilities of most major religions, Piss Christ by Andres Serrano was the subject of an attack in Victoria's State Gallery which subsequently closed the exhibition to the public amid perceived "safety" concerns.
2. Painting in Disputed Exhibit Attacked by Man at Museum
ROBERT D. McFADDEN
New York Times , December 17, 1999
5.Decision to cancel Sensation exhibition turns political
ABC News online; The World Today - Tuesday, November 30, 1999
$250 FINE FOR OFILI VANDAL
A short story on the punishment dealt to heiner.
BMA, GUILIANI FILE COUNTER SUITS AS SENSATION OPENS
Arts Wire, October 5, 1999 Volume #8 No. #40
An article on the exhibition and surrounding courtcase with Giuliani.
Protester hurls dung at Brooklyn Museum
CbC Radio Arts
Story on Scott LoBaido's Dung throwing and links to other related stories.
A comprehensive links resource to stories about the Sensation Exhibition