A Polish man was jailed for two years in Britain on Thursday for defacing a mural by US artist Mark Rothko at London's Tate Modern gallery.
Wlodzimierz Umaniec, 26, on October 7 scrawled his name on Rothko's "Black On Maroon", which is worth between £5 million and £9 million ($8-$14.5 million, 6.2-11.1 million euros).
Umaniec, who lives in Worthing, southeast England, admitted criminal damage to the value of more than £5,000 -- but estimates suggest restoration of the painting will cost around £200,000.
Umaniec, who co-founded the artistic movement "yellowism", stepped over a barrier and daubed his name and "12, a potential piece of yellowism" on the artwork before fleeing.
Outside court before the sentencing, Ben Smith, who called himself a "yellowist", attempted to explain the concept: "Everything is equal. Everything is art. Everything is a potential piece of yellowism."
When sentencing Umaniec at Inner London Crown Court, judge Roger Chapple told him his actions were "entirely deliberate, planned and intentional".
He said it was "wholly and utterly unacceptable" to promote his movement by "damaging a work of art" which the judge called a "gift to the nation".
Rothko donated the painting to the Tate in 1969.
Chapple said Umaniec was "plainly an intelligent man", but the effects of security reviews forced by his actions will "distance the public from the works of art they come to enjoy".
Work to restore the painting will be complex and take around 20 months, the court heard, because the ink Umaniec used had permeated the paint layers and the canvas beneath.
The defaced painting is one of Rothko's Seagram murals commissioned by New York's Four Seasons restaurant in 1958.
It arrived in London for display at Tate Modern's sister gallery on February 25, 1970 -- the day the artist committed suicide aged 66.
A large-scale painting by Rothko fetched $86.9 million at a New York auction in May, setting a record for any contemporary work of art.
The Russian-born expressionist painter became a giant of the modern art world through his simplified and colourful compositions inspired by mythology and primitive art.
