In 1963, when Daniel Mannix died (at 99), it was too soon to judge the impact of that council, but in the half-century that followed, the church - and the world - changed immeasurably.
It seems so strange now, but it was an interesting place to be, at that pivot point in history. And Griffin was adept at finding himself in interesting places at interesting times.
Mannix, his era and close associates (including B.A. Santamaria and John Wren), consumed Griffin's scholarly energies for decades. Griffin's iconoclastic Mannix entry in the Australian Dictionary of Biography sparked fierce reaction when it was published in 1986.
It was deemed heresy (Santamaria and George Pell were among its most vehement repudiators), and all the more heinous for coming from an insider - a Catholic historian who, ironically, was one of the beneficiaries of Mannix's promotion of Catholic higher education and Catholic lay action.
Griffin was the very model of what Mannix had championed: the elevation of Catholics into the educated, professional class. Rhetorically gifted, Griffin demythologises but does not underestimate his subject, which makes his Mannix all the more fascinating.
His book provides careful historian's justice to the many controversies that constellated around Mannix during his long life. He gives a detailed account of the mutations of Mannix's Irish nationalism, which comprehended his courtly reception of British royalty when he was president of Ireland's Maynooth seminary, his ''say no'' interventions in Australia's conscription referenda during the First World War, his strident criticism of England before and after he was intercepted by the British Navy and prevented from landing in Ireland in 1920, and his lifelong friendship with the ''machiavellian'' Eamon de Valera.
His other great friendship, with B.A. Santamaria, Australia's most powerful and politically divisive lay Catholic, is dissected by Griffin's friend, the writer Paul Ormonde, who was called in to complete the final chapter when Griffin died in 2010.
Griffin's account will continue to have its critics, particularly in Catholic circles. Let that debate play on. But with sexual abuse in the Catholic church an open scandal, Griffin's work has a new resonance. Daniel Mannix: Beyond the Myths reads like a handbook for the analysis of mystique, of power, of celebrity and its aetiology, of warranted stature and of clay feet.
Times change but we remain drawn by charisma and by demagoguery, so it is instructive - and profoundly moving - to read this portrait of a man who earned his reputation for sanctity and for controversy in another era. What made him? What qualities in him attracted such a following? Can we ever know? Mannix wilfully destroyed most of the personal papers that might have illuminated his private soul. What is the cost of priestly isolation, priestly loneliness?
This was a man who, at the end of his life, could so little bear to be touched that he cut his own hair. Yet he touched millions of lives. He lived austerely and strode the world magisterially. He was humble and arrogant, prayerful and powerful. Humankind is irrevocably drawn to charismatic leaders, and Mannix was undoubtedly one such.