The artist Sir Kyffin Williams has left £500,000 to charities and other bodies in his will, with his estate valued at worth more than £6m.
This painting, left to the library, could be worth £1m
The National Library of Wales in Aberystwyth has been bequeathed much of Sir Kyffin's own art collection, running to hundreds of works.
A painting of Saint Jerome by Italian artist Domenichino is currently being valued and could be worth around £1m.
Sir Kyffin died of cancer in Anglesey, aged 88, in September 2006.
Among the beneficiaries of Sir Kyffin's estate, which has been valued at £6,187,017 net, are the Royal Cambrian Academy of Art in Conwy and printing press Gwasg Gregynog, based in Newtown, Powys, which both receive £100,000.
The Council for the Protection of Rural Wales (CPRW), the Tabernacle arts centre in Machynlleth, Powys, the Ucheldre Centre in Holyhead, Anglesey and the Artists Benevolent Fund which helps the widows of artists, each received £50,000 in the will, solicitor Huw Elwyn Jones confirmed.
Furniture from Sir Kyffin's rented home on Anglesey was given to Bangor University along with a number of paintings.
The National Museum Wales was also given some of the late artist's pieces, which have sold for as much as £75,000.
The Anglesey-born artist owned no property, having rented on the island, did not marry or have children and according to his godson Nicholas Sinclair, lived a frugal life.
His money came from the sale of his own work and from paintings he owned by other artists. The Domenichino painting was worth around £1m, estimated Mr Sinclair.
He was also not surprised to learn that Sir Kyffin had left so much to Welsh charities and organisations.
"He was an artist and the arts were incredibly important to him," he said.
"He gave a lot to charity in his lifetime.
"His great passion in life was painting and he also had a very close circle of friends so the car he was driving and the units in his kitchen were irrelevant to him."
The National Library of Wales said Sir Kyffin had bequeathed it around 250 oils on canvas, approximately 600 water colours and drawings, diaries, photographs and slides, original manuscripts of books written in long hand by the artist, several sketch books, letters and even passports.
Sunset over Anglesey - Sir Kyffin Williams' last painting
Works given to or purchased by him are also among the bequest to the library, including the Domenichino and paintings by Sir Kyfffin's great-grandmother.
Paul Joyner, head of purchasing and donations for the library, said he suspected it would take around two years to catalogue everything.
The library would work very closely with the £1.5m Oriel Kyffin Williams, which is scheduled to open on St David's Day 2008, to loan paintings, he said.
A large retrospective detailing Sir Kyffin's place in Welsh art would also happen but not for a number of years yet, said Mr Joyner.
"There has been a long association between the library and Sir Kyffin," said Mr Joyner.
"Someone spotted him as an important artist back in the 1940s and since then we've felt that he was essential and central to art in Wales.
"It was a reciprocal relationship. He felt that the library was one of the hubs of Welsh culture and he felt very strongly that his legacy was preserved."