Lord Roberts of Conwy has died aged 83.
The former Conservative minister in the Thatcher and Major governments was MP for Conwy from 1970 until 1997 when he was awarded a life peerage.
He is credited with taking legislation promoting the Welsh language through Parliament.
David Cameron paid tribute to Lord Roberts and called him a “great Conservative” who “did so much for Wales”.
Wales First Minister Carwyn Jones said: “I am saddened to hear of the death of Lord Roberts of Conwy and my thoughts go out to his family and friends at this time.
"Lord Roberts was a leading figure in Welsh politics for more than 30 years. As well as a long career in the Welsh Office he will be particularly remembered for his work on the Welsh language and for piloting the Welsh Language Act in 1983.
“He will be greatly missed by Welsh politics as a whole.”
Huw Jones, chairman of the Welsh language broadcaster S4C Authority said the former journalist was a “guardian angel” to the service.
“Alongside his measured and careful style, he had humour and mischief in his eye and great personal warmth.
"He made a huge contribution at a critical time for the Welsh language and he will be greatly missed.”