Tedi Millward, Prince Charles’ Welsh tutor and an inspirational figure for the Welsh nationalism movement, has died aged 89.

Dr Millward, who taught at Aberystwyth University, tutored Charles in Welsh ahead of his investiture as Prince of Wales in 1969.

The pair’s lessons featured in an episode of Netflix series The Crown titled Tywysog Cymru, Welsh for Prince of Wales.

Dr Millward was also hailed as a driven campaigner for Welsh culture, identity and independence, with Plaid Cymru paying tribute at the passing of a “Welsh giant”, and independence group YesCymru citing him as an inspiration.

Born in Cardiff in 1930, Dr Millward co-founded the Welsh Language Society, which is credited with helping establish Welsh as an official legal language in 1967.

He was also a prominent member of Plaid Cymru, running unsuccessfully for the seat of Cardiganshire in a Westminster election.

His daughter, London-based singer and actress Llio Millward, said she thought of her father as a nationalist first.

“My beloved father was a deeply principled man who dedicated his life and his life’s work to Wales,” she posted on Facebook.

“He was a man of the highest integrity and a true gentleman in every sense.

“Although in personality he was very self-effacing and modest, he achieved phenomenal heights and lived his whole life with great purpose and passion for Wales, the Welsh language and the people of Wales.”

I wasn’t in favour of (Charles) ­becoming Prince of Wales ... (but) in the end, I got on quite well with him and he was good to get to know

Tedi Millward

In one of his final interviews late last year, Dr Millward said he had been opposed to Charles becoming Prince of Wales but that the pair developed a warm relationship.

“I wasn’t in favour of him ­becoming Prince of Wales. And he knew it,” Dr Millward told The Sun.

“(But) in the end, I got on quite well with him and he was good to get to know.

“I found him intelligent and quite charming. We became quite close.”

Actor Mark Lewis Jones, who played Dr Millward in The Crown, said he had made an “immense” contribution to Wales.

“I had the absolute privilege to play this Welsh giant. His contribution to Wales and its language is immense. A great loss,” Lewis Jones tweeted.

YesCymru said Dr Millward was a symbol of “a brave generation” who had stood up for Welsh identity.

“It’s cos of Tedi Millward and others that @Cymdeithas (YesCymru) was formed – against a background of hatred towards them and the Welsh language by many Welsh people who thought Welsh was only for chapel and not the modern world.

“A brave generation who refused to lie-down and see Welsh die,” the group tweeted.