LONDON — Diehard romantics, celebrity hounds and Anglophiles feasted on last month’s royal wedding, replete with a fairy-tale prince, Posh and David Beckham and enthralling British pageantry. The estimated worldwide television audience of 2 billion got just what they hoped for on April 29, along with an unexpected, and perhaps unsought, bonus: an unapologetic affirmation of the truth, beauty and transformative power of Christian marriage.

At Westminster Abbey, the gravitas of the nuptial sacrament, the fruits and ends of marriage intended by the Creator, and the sacrificial nature of genuine married love were on display, at times outshining the British Monarchy’s trove of Crown Jewels.

Facing a congregation that included a global contingent of monarchs, the ex-mistress — and now second wife — of the groom’s father; Elton John and his “husband” — proud parents of a boy delivered through a surrogate mother last Christmas — and assorted commoners from a nation that has witnessed a precipitous decline in marriage, the Anglican Bishop Richard Chartres of London delivered a rousing sermon that could have been crafted by Pope Benedict XVI himself.

He began with a quotation from St. Catherine of Siena, noting that it was her feast day: “Be who God meant you to be, and you will set the world on fire.”

“In a sense every wedding is a royal wedding with the bride and the groom as king and queen of creation, making a new life together so that life can flow through them into the future. William and Catherine, you have chosen to be married in the sight of a generous God who so loved the world that he gave himself to us in the person of Jesus Christ. And in the Spirit of this generous God, husband and wife are to give themselves to each another,” stated Bishop Chartres.

“A spiritual life grows as love finds its center beyond ourselves. Faithful and committed relationships offer a door into the mystery of spiritual life in which we discover this; the more we give of self, the richer we become in soul; the more we go beyond ourselves in love, the more we become our true selves and our spiritual beauty is more fully revealed,” he continued, with the bride and groom listening intently.

Once upon a time, the “goods” of marriage were broadly understood to include the procreation of children. Though it is still written into canon law, that expectation now competes with many options in today’s society — one reason, perhaps, for growing public acceptance of same-sex “marriage” in the West. Yet in the context of a royal marriage that will hopefully beget an “heir and a spare,” children are not optional, and they are expected to be the direct fruit of the “one flesh” union of husband and wife.

The royal marriage of Kate and William was executed against the backdrop of scandal and tragedy — the collapse of the marriage of Prince Charles and his late wife, Diana, who was herself a victim of her own parents’ acrimonious divorce. The bishop of London did not address these events. But he readily acknowledged the reality of human frailty and suggested that in the absence of a deep faith in God, sin and human imperfections would wreak even greater havoc on married couples and their families.

“As the reality of God has faded from so many lives in the West, there has been a corresponding inflation of expectations that personal relations alone will supply meaning and happiness in life. This is to load our partner with too great a burden,” he suggested.

Instead of turning to New Age nostrums or the reflected glory of a celebrity-obsessed culture, he advised the bride and groom to place their trust in God and maintain a ready supply of forgiveness.

Before the ceremony commenced at the cathedral, television commentators made much of the fact that Kate and William had lived together for years and were thus better prepared to both avoid the tragedy that struck Princess Diana and manage the extensive public obligations and intrusions on their privacy.

Reflecting on the growing tolerance of cohabitation, one British commentator couldn’t help but note the transformation in cultural attitudes: “It used to be called ‘living in sin,’” she remarked with a giggle and an expression of amazement.

According to the British Office of National Statistics, 231,490 couples married in 2009 — down from 232,990 in 2008 and the lowest total since 1895. Meanwhile, divorce rates have risen. Predictably, some British groups have argued for providing legal benefits to cohabitating couples, a familiar trend in much of the West, as the young find it harder to identify the specific value of marriage or clearly distinguish between marriage and cohabitation, which, of course, the Catholic Church continues to teach on (see Catechism teaching on the Sixth Commandment).

As Blessed John Paul II noted in Familiaris Consortio (On the Role of the Christian Family in the Modern World), “In the first place, the gift of the body in the sexual relationship is a real symbol of the giving of the whole person: such a giving, moreover, in the present state of things cannot take place with full truth without the concourse of the love of charity, given by Christ. In the second place, marriage between two baptized persons is a real symbol of the union of Christ and the Church, which is not a temporary or ‘trial’ union, but one which is eternally faithful. Therefore, between two baptized persons, there can exist only an indissoluble marriage. ... True education in genuine love and in the right use of sexuality, such as to introduce the human person in every aspect, and therefore the bodily aspect too, into the fullness of the mystery of Christ” is needed.

The bishop of London, who reportedly advised the couple before their nuptials, did not specifically address the morality of cohabitation. But his remarks left the strong impression that the solemn exchange of nuptial vows was something quite different from a live-in relationship and that the abundant graces of matrimony offered vastly greater benefit — particularly for the children to come — than “playing house.”

“As we move towards our partner in love, following the example of Jesus Christ, the Holy Spirit is quickened within us and can increasingly fill our lives with light,” he said. “This leads to a family life which offers the best conditions in which the next generation can practice and exchange those gifts, which can overcome fear and division and incubate the coming world of the Spirit, whose fruits are love and joy and peace.”

In an age of “disenchantment,” when the central institutions and values of the West are more likely to prompt skepticism than affirmation, the bishop of London’s sermon provided a window on the sacrament of matrimony. At the very center of all the pomp and pageantry stood the sacrament — the words, actions and materials that affirm the marriage vows and lay the foundation for the indissoluble bond of husband and wife.

The bishop of London acknowledged the fears and hopes of a modern society that has come to doubt the existence not only of a loving God, but of love itself. To a skeptical world, he proposed that the survival of the institution of marriage, rightly understood, could help secure the fulfillment of our common hopes.

“We shall not be converted to the promise of the future by more knowledge, but rather by an increase of loving wisdom and reverence, for life, for the earth and for one another,” he concluded.

To which the congregation at Westminster gave in reply — with perhaps mixed emotions and some perplexity — a vigorous “Amen.”

Register senior editor Joan Frawley Desmond writes from Chevy Chase, Maryland.