By Mark Devenport
Political editor, BBC Northern Ireland
It sits in a side room at the back of the disused Senate Chamber inside Stormont's Parliament Buildings.
The painting depicts King William III's arrival in Ireland
A monumental canvas apparently depicting the arrival of King William III in Ireland in the 1690s, it was purchased by the old Northern Ireland government back in March 1933.
But the controversial work of art was vandalised soon afterwards and has not been on public display for more than 20 years.
Now some say the time has come to hang it somewhere more prominent.
Buying the picture, thought to be the work of William of Orange's court artist Pieter van der Muelen, cost the old Stormont government £209 and four shillings.
Unionist MPs cheered when they heard of its acquisition. But those cheers gave way to bewilderment when the canvas was unveiled.
There in the foreground is a figure which looks like King Billy on his white charger.
But floating above him on a cloud is someone who appears to be Pope Innocent XI, apparently blessing his ally as he makes his way towards the Battle of the Boyne.
A figure believed to be Pope Innocent XI appears to bless William III
For those who celebrate the victory of the Protestant King William over the Catholic King James this may be an inconvenient reminder of the facts of 17th century great power politics.
But the Ulster Museum's Keeper of History, Trevor Parkhill, explains that "there is a well documented record that the Pope had a 'Te Deum' sung in the Vatican on hearing the outcome of the Battle of the Boyne".
"As Stalin would have said, they were objective allies in the 1690s against the Sun King Louis XIV who was at that time the most dominant authority in power in Europe," he added.
Back in the 1930s some couldn't stomach that kind of talk.
In May 1933 a group of visitors from the Scottish Protestant League were touring Parliament Buildings when they came face to face with King Billy and the Pope.
An enraged Glasgow councillor, Charles Forester, threw red paint over Innocent XI.
His companion Mary Ratcliffe slashed the canvas with a knife. Both were arrested and fined £65 when they appeared in court in Downpatrick.
The painting was restored for a cost of £32 and 10 shillings.
The authorities at Stormont decided it would be a wise move to shift it to a less exposed spot.
Its precise whereabouts inside Parliament Buildings were unknown from 1936 until 1975 when the picture was moved to the Belfast Public Record Office.
It went on public display there until 1983 when it was returned to the speaker's office at Stormont.
Art experts dispute whether the painting is the work of Pieter van der Meulen and whether the subject really is King William of Orange.
But the attack on the canvas has made it part of Stormont folklore.
Damian McCarney, who writes for Daily Ireland and the Andersonstown News recently had a private viewing.
In his opinion, "a reproduction of it doesn't do it justice".
"Whenever you first encounter the painting you are awe struck by the size of this epic tale unfolding in front of you," he said.
"So in a visual sense it deserves to be displayed.
"But I believe the story behind it will capture the imagination of a lot of people as well.
"Here's a painting which attracted controversy and was attacked for no justifiable reason.
"I think a lot of people can respond to that. It has echoes of the sectarian past and now we're coming to a more tolerant period in history now is the time for it to be restored to its rightful place in the southern corridors of the Stormont assembly."