They arrived at the church of St. Stephen on Walbrook. Walbrook had been a stream in Roman times, and was now assumed to be a sewer flowing somewhere beneath the street of the same name, though no one was volunteering to go down and verify this. It was a good omen for the day, because this was Daniel’s favorite church. (1) Wren had put it up early in his career—come to think of it, during the same years Leibniz had been toiling on the calculus. It was all domes and arches, as white and pure as an egg; and whatever uplifting thoughts its parishioners might think as they filed into it, Daniel knew it was Wren’s secret anthem to Mathematicks. (2) Thomas Ham, his goldsmith uncle, had lived and worked close enough to hear the hymns being sung in this church. His widow Mayflower—who late in life had converted to Anglicanism—had attended services there with her surviving son William. (3) When King Charles II had ennobled Thomas Ham by way of apology for absconding with all of his customers’ deposits, he had named him Viscount Walbrook, and so to Daniel the Church of St. Stephen Walbrook felt almost like a family chapel.