Mr Ronald (top right) is one of five men on trial at the High Court in Edinburgh
A lawyer has been lauded as the person "principally responsible" for getting a stolen da Vinci back to its owner.
Marshall Ronald was said to have become "obsessed" with the Madonna of the Yarnwinder project and then "greedy".
However, his defence advocate Donald Findlay QC said that did not make him an extortionist.
Mr Ronald is one of five men on trial at the High Court in Edinburgh who deny conspiring to extort £4.25m for the painting's return.
In his closing speech to the jury, Mr Findlay said it was an "incontrovertible fact" that but for his client's efforts the painting would not have been recovered.
It was stolen from the Duke of Buccleuch's Drumlanrig Estate in Dumfriesshire in August 2003.
Mr Findlay admitted that Mr Ronald had done things that were wrong, such as taking money from his law firm's client account.
"That is abhorrent to all lawyers," he said.
"He knows it and is ashamed of it - but that does not make him an extortionist."
He told the jury: "If you think he was greedy you may well be right but that is not the issue before you today."
Mr Findlay said it was not "a court of morals or social attitudes or personal opinions".
Proved its case
"You are asked only to decide if the Crown has proved its case beyond all reasonable doubt," he said.
Mr Findlay said Mr Ronald had committed no crime in trying to find out if there was a reward, nor in saying that it had to be at least £700,000 to acquire the painting from the person in possession of it.
Neither, he said, would it have been a crime for the duke to pay whatever sum he saw fit to get the painting back.
On trial with Mr Ronald, 53, are Robert Graham, 57, and John Doyle, 61, all from Lancashire, Calum Jones, 45, of Renfrewshire, and David Boyce, 63, of Lanarkshire.
They deny conspiring to extort pounds £4.25m between July and October 2007. The trial continues.