Montal, Barca president between 1969 and 1977, has been praised since his passing for signing Johan Cruyff from Ajax and re-establishing the club's Catalan identity during and after the dictatorship of Francisco Franco.
He was instrumental in persuading the Spanish soccer federation to remove a ban on signing foreign players, which paved the way for the arrival of Dutch playmaker Cruyff in 1973.
Cruyff, who died of lung cancer last year, inspired Barca to a first league title in 14 years in his first campaign and is seen by many as the godfather of the modern Barcelona, coaching the club to their first ever European Cup in 1992 and instilling a style of football imitated by future managers.
Montal also promoted the Catalan language, which under Franco was banned in public spaces.
The club said in a statement he had printed membership cards and a newsletter in Catalan and was called to order by the authorities for making stadium announcements in the regional language.
"Agusti Montal was a great man and an extraordinary FC Barcelona man," current president Josep Maria Bartomeu said.
"He led Barca during the final years of Franco and at the beginning of the transition [to democracy]. He converted the Nou Camp into a space for freedom where members could express their ideas... We will miss his values, his warmth and his advice."
(Reporting by Richard Martin; Editing by Mark Trevelyan)
