Former first minister Rhodri Morgan has died, aged 77.
Wales has “lost a father figure”, his successor Carwyn Jones said.
He was elected as an MP in 1987 and became an AM when the assembly was created in 1999.
Mr Morgan became first minister nine months later, replacing Alun Michael who had stood down. He is widely credited with having brought stability to the fledgling assembly after a turbulent start to the new institution.
He is survived by his wife, Julie, two daughters and a son.
Mr Jones said: “Wales hasn’t just lost a great politician, we’ve lost a real father figure.”
He said he was “funny, clever, engaging on almost any topic”.
“I owe him a great deal, just as we all do in Wales,” Mr Jones said.
“He did so much to fight for, and then establish devolution in the hearts and minds of the public in our country.”
Former Labour Welsh secretary Lord Hain said: “As first minister Rhodri was both the father of devolution and the father of the nation.
“He did more than anyone to bed down and ensure the new Welsh Assembly gained widespread legitimacy.”
Calling him a “unique populist intellectual”, he added he was a “towering figure in every sense whom we will all miss”.
Labour’s Wayne David called Mr Morgan a “giant of Welsh politics”.
Rhodri Morgan had served as first minister in a coalition with Plaid Cymru, a party then led by Ieuan Wyn Jones, for two and a half years.
Mr Jones said: “He was very easy to work with, and he was very likeable, extremely loyal and highly knowledgeable. It wasn’t easy for him to deliver the coalition in sections of his party, but Rhodri stood firm and we agreed a very progressive programme of government.”
Welsh Secretary Alun Cairns, himself a former AM who sparred with Mr Morgan in the Senedd chamber, said he was “a significant politician” and “great servant to Wales”, while his party colleague Stephen Crabb said the former first minister “made a big contribution to Welsh and UK politics”.
Plaid Cymru leader Leanne Wood said he was “was much respected across the political spectrum and led Wales with distinction during a crucial period in Welsh history.”
‘He spoke like no other politician’
By Tomos Livingstone, BBC Wales political correspondent
Rhodri Morgan stabilised Welsh devolution after its rocky first year, and spent nine years as first minister in his own idiosyncratic style.
At a time when soundbites were the norm, he spoke like no other politician – his response to being asked whether he wanted to lead the yet-to-be-created assembly was “do one-legged ducks swim in a circle”?
In office he pursued a strategy of differentiating his administration from Tony Blair’s New Labour government, using the new devolved powers to opt-out from Blairite reforms to health and education.