Sir Patrick Stewart has paid tribute to John Barton, a co-founder of the Royal Shakespeare Company who has died aged 89.

Barton died on Thursday morning having worked with the company since he found it with the late Sir Peter Hall in 1960, the RSC announced.

Sir Patrick said it was with “great sadness” that he learned of Barton’s death.

“But the sadness is overwhelmed by the gratitude, respect and love I had/have for him,” he tweeted.

“No one in my career had the impact that John had and the names William Shakespeare and John Barton will be for me forever united.”

RSC artistic director Gregory Doran said Barton was “one of the greatest influences in the acting of Shakespeare of the last century”.

He also praised Barton for directing numerous “definitive” productions of Shakespeare’s plays, including Twelfth Night in 1969 with Dame Judi Dench and The Merchant Of Venice with Sir Patrick in 1978 and David Suchet in 1981.

“But perhaps John’s greatest influence on the company, and hence to the profession, was his passion for the verse, and his ability to uncover the clues that Shakespeare wrote into the text to enable actors to deliver it with freshness and vivid clarity,” Doran added.

“Although frail in body at the last, he was always mentally alert and retained his sense of curiosity until the end.”

Josie Rourke, the Donmar Warehouse’s artistic director, praised Barton for being “fierce, funny and so very tolerant” while coaching her through her production of King John in 2006.

Barton was living in a care home in west London having lost his wife Anne in 2013, the RSC said.