Some demolitions were controversial. The Van Horne Mansion, the centre of Square Mile society since the 1930s was demolished by promoter David Azrieli in 1973, igniting a vigorous public debate regarding conservation of historical buildings, and the reasons for which a building should be preserved. The demolition of the Van Horne mansion led to the establishment of Heritage Montreal to protect historic buildings at the provincial level. The architectural character of the neighbourhood stabilized, but the original Square Mile as it had been had already changed beyond recognition.