Terry Jones, Monty Python star and co-founder, has passed away. He was 77.

His death follows a four-year battle against frontotemporal dementia, or FTD, a rare form of dementia that left him unable to speak.

“We are deeply saddened to have to announce the passing of beloved husband and father, Terry Jones," his family said in a statement. "Terry passed away with his wife Anna Soderstrom by his side after a long, extremely brave but always good humoured battle with a rare form of dementia, FTD.”

The Welsh actor and comedian directed and starred in some of the comedy troupe's most beloved works, including Life of Brian. He was born in Colwyn Bay and studied at Oxford University, where he met future Python collaborator Michael Palin.

"Terry was first of all an enormous enthusiast. He threw himself into things with such passion and such energy, and he really refused to take on things which didn't excite him and which didn't feel different from what else was around," Palin said of the late comedian on BBC Radio Four's The World at One.

Jones wrote and starred in Monty Python's Flying Circus TV show, which aired in 1969 and catapulted the troupe to stardom, and co-directed the cult-classic 1975 film Monty Python and the Holy Grail. He was renowned for his hysterical falsetto voices in depictions of middle-aged housewives, including his iconic line from The Life of Brian: "He's not the Messiah, he's a very naughty boy."

The official Monty Python Twitter account paid tribute to Jones, saying "two down, four to go," in reference to fellow Monty Python star Graham Chapman, who passed away from cancer in 1989. Fellow troupe member John Cleese also paid tribute to Jones via social media.

Farewell dear Terry J. Two down, four to go. Love Terry G, Mike, John & Eric pic.twitter.com/RbVrAAJz2d

— Monty Python (@montypython) January 22, 2020

Just heard about Terry J

It feels strange that a man of so many talents and such endless enthusiasm, should have faded so gently away...

Of his many achievements, for me the greatest gift he gave us all was his direction of 'Life of Brian'. Perfection

Two down, four to go

— John Cleese (@JohnCleese) January 22, 2020

Tributes have poured in via Twitter from fellow comedy giants.

Farewell, Terry Jones. The great foot has come down to stamp on you. My god what pleasure you gave, what untrammelled joy and delight. What a wonderful talent, heart and mind

— Stephen Fry (@stephenfry) January 22, 2020

Terry Jones was the only Python who agreed to appear in The Young Ones. It was like affirmation from God himself. This was the man who’d directed what was, and still is, the funniest feature film ever made. We loved him for it, and always will. Sadly, he’s eaten his last mint...

— Adrian Edmondson (@AdrianEdmondson) January 22, 2020

Jones is survived by Soderstrom, his son Bill and daughters Sally and Siri.