Two leading figures in the Scottish National Party have announced they will step down as MSPs.
Michael Russell, who represents Argyll and Bute, will not stand in the Holyrood election next year.
Mr Russell, who will be 67 in August, said it may be time for someone younger to represent the constituency.
It has also been announced that Stewart Stevenson, who represents Banffshire and Buchan Coast for the SNP, will leave parliament at the election.
He is 74 and has been an SNP activist since 1961.
Announcing the decision to his constituency association, Mr Russell said: "I will be 67 this summer and 72 at the end of the next Parliament.
"Argyll & Bute is a massive area to cover - with 23 inhabited islands and a large swathe of the mainland - and I am getting to the stage of thinking that someone younger would be better able to fulfil all the demands of the constituency.
"It is, I think, much better I say that now than wait for someone else to do so."
The Kent-born campaigner for Scottish independence
- Mike Russell was born in Bromley, Kent in August 1953
- Grew up in his father's home town of Troon, Ayrshire
- Studied Scottish Literature and History at Edinburgh University
- A published writer, television producer and director
- Founder and first director of the Celtic Media Festival
- Member of the Scottish parliament since 1999 (except for 2003-7 term)
- Has represented Argyll and Bute at Holyrood since 2011
Although initially a Labour supporter as a student, Mr Russell joined the SNP in 1974.
He held a number of constituency, and then national, offices in the party before becoming its first full-time chief executive in December 1994.
He was elected to the Scottish parliament in the first elections in 1999, although he failed to keep his seat in 2003.
Mr Russell first became a minister, responsible for the environment, when he was elected in 2007.
He said his decision to leave parliament did not mean he would stop campaigning for Scottish independence.
"After next May I still intend to be active in the political sphere," he said.
"I think of my decision as stepping back from some current roles, not stepping away from my commitment to our country and the better future it can have and should choose.
"Independence is so much closer than it was when I first voted for the SNP 46 years ago. I hope I have contributed something to that success and I still hope to contribute more but in a different way and role."
Minister for transport
Stewart Stevenson's retirement comes after serving in the Scottish parliament since 2001.
He was born in Edinburgh and grew up in Cupar in Fife.
Mr Stevenson studied mathematics at the University of Aberdeen and worked in information technology with the Bank of Scotland before becoming a full-time politician.
His roles in government have included minister for transport.
Announcing his retirement, he said: "I will miss working with, and for, so many people in the constituency, but for the year next I shall continue to work hard to represent the people of the North-east and I hope to say a personal thank you to the many people who have been part of my life over the years in both the constituency and at Holyrood.
"My leaving Parliament does not mean that I shall be leaving politics.
"Until Scotland can make its own decisions as a normal, independent country, co-operating with friendly neighbours for moral causes, I shall continue to lend my efforts wherever and whenever I can."
Fellow SNP MSPs James Dornan, who represents Glasgow Cathcart, and Gail Ross, who represents the Caithness, Sutherland and Ross constituency, have also said in the last week that they will not seek re-election next year.