LONDON — It was an electrifying and unexpected moment in the midst of what had been a (mostly) by-the-book British wedding service. And as it went on, you could practically feel centuries of tradition begin to peel away.

Here was a relaxed, charismatic African-American bishop — Michael Bruce Curry, the head of the Episcopal Church — speaking to British aristocrats and members of the royal family in the cadence of the black American church.

But what was striking was not just his message, of love and inclusion; or his tone, which was soaring and magisterial; or his obvious delight in the matter at hand. It was the sheer fact of his prominence in a service that featured a fair number of ecclesiastical heavyweights, including the archbishop of Canterbury (who tweeted his admiration of the bishop).

The service, carefully put together by Meghan Markle and Prince Harry, included all the usual traditional elements, like a reading from the Bible by Harry’s aunt, the sister of Diana, the Princess of Wales.