The modern history of the Catholic Church has rarely followed the historical arc imagined for it.

In the early 19th century, the Church in France was awash in Jacobin-drawn blood, and the Church throughout Europe was reeling from two papal kidnappings by Napoleon. No one imagined that, in the decades just ahead, Catholicism would flourish in the new United States and that the Church’s mission to sub-Saharan Africa would begin in earnest, led by new religious orders founded in the aftermath of the French Revolution.

In 1870, when Piux IX retreated behind the Leonine Wall and became the “prisoner of the Vatican,” Europe’s great and good thought the papacy a spent force in world affairs. Eight years later, Leo XIII, Pius IX’s successor, elected as an elderly placeholder, redefined the papacy as an office of moral persuasion and gave it new salience during the third-longest reign in recorded history.

When Pius XII died on October 9, 1958, the character and practice of Catholicism seemed fixed, permanent, even immutable. Less than three months later, Pius’s successor, John XXIII, announced his intention to summon a new ecumenical council. That council would, among other things, unleash decades of instability in Catholic life unimaginable in the mid-1950s.

In 1962, as Pope John’s council began its work, the Swiss theologian Hans Küng was riding high; his international bestseller, The Council: Reform and Reunion, seemed poised to define much of Vatican II’s agenda, and the previously obscure Tübingen theology professor was an international media star. Fifty years later, no serious observer of the Catholic scene imagines Hans Küng to be a serious theologian; meanwhile, Küng rants on in the world press, denouncing the world’s bishops as “almost as extreme” as those German generals who swore “an oath of allegiance to Hitler,” comparing St. Peter’s Square and the millions of pilgrims who flock there to a “Potemkin village” replete with “fanatical people,” and telling that nuanced theological organ, Britain’s Guardian, that “the Vatican is no different from the Kremlin,” for “just as Putin as a secret service agent became the head of Russia, so Ratzinger, as head of the Catholic Church’s secret services, became head of the Vatican.” (One may safely assume that the quondam Wunderkind of theological dissent never imagined this outcome when he engineered Joseph Ratzinger’s appointment to the Tübingen faculty shortly after Vatican II concluded.)

At the council’s opening, hopes for a new era of ecumenical comity ran high, and the healing of the breach between the Church of Rome and the Church of England, created by Henry VIII, Edward VI, and Elizabeth I, seemed close at hand. Fifty years later, the Episcopal bishop of California, Marc Andrus, wrote a letter to the people of his diocese denouncing the new Catholic archbishop of San Francisco, Salvatore Cordileone, for Cordileone’s support of California Proposition 8 and his defense of marriage rightly understood. The Episcopal Church, Andrus bleated, would “make no peace with oppression,” for the “recognition of the . . . rights . . . of lesbian, bisexual, gay, and transgendered people . . . [is] as core to our proclamation of the Gospel as our solidarity with . . . the Earth.” (One may safely assume that the archbishop of Canterbury in 1962, Arthur Michael Ramsey, an Anglo-Catholic, could not have imagined a churchman remotely resembling Marc Andrus, a neo-gnostic.)

At the council’s conclusion, the Catholic Church looked forward to a new dialogue with modernity, exemplified by the open, if secular, humanism of an Albert Camus or a Roger Garaudy. Three years later, the upheavals of 1968 ushered in the era of what the Canadian philosopher Charles Taylor dubbed “exclusive humanism,” and over the next four decades, much of Western high culture declared itself interested, not in dialogue with Catholicism, but in driving the Catholic Church (and its allegedly oppressive teachings on the nature and ethics of human love) out of public life entirely.

All of which will remind the biblically alert that the first (and revealed) history of the Church, the Acts of the Apostles, ends with an unexpected shipwreck — which becomes, in turn, a surprising opening to a new phase of the Church’s mission.

Things rarely turn out as one might expect in the Una Sancta.