Thinking how hard poor Dorothy Wiseman worked at producing a child every two years for so long, I looked at the burials. Elizabeth, Sarah and Anthony all died within a short time of Dorothy having children of those names.

Then I noticed something else. Unlike the baptisms, the burials were arranged alphabetically. In looking for Wiseman I noticed other, similar names such as Wistham and Wiseham. A Solomon Wistman of Long Lane, Bermondsey, was buried on April 9, 1769. This was a year after the birth of a Solomon Wiseman in 1768. Was it possible that this was the same person?

With horror I realised that Solomon Wisemans were starting to proliferate like weeds in every parish, recorded under any variant of his name that semi-literate clerks might dream up. My Solomon Wiseman might be any of them, or none.

I replaced the blue artificial leather books on their shelves, put my coat on and thanked the tweed volunteers. As I left, one of them gave me a pamphlet: Searching for your Convict Ancestor. I stuffed it into my bag.

It was still raining. Out on the street, where the buses were roaring up and down Clerkenwell Road, I seemed to hear Solomon Wiseman laughing.

Later I sat on the bed in my hotel room and assembled everything. I ignored all the quasi-Wisemans—those Wistmans and Wisehams—hovering around the object of my search. With the new data (or perhaps-data) from the Society of Genealogists, I was going to arrange all the Wisemans into some kind of coherence.

It was infuriating. The same names and dates and places recurred with small variations. I had the maddening feeling that all these interlocking pieces of information could join up—but I didn’t know how. There had to be a pattern, because Solomon Wiseman really had existed.

It took a while, but I came up with a scenario. I counted six Wiseman households in London. Four of them lived north of the river, in the parish of St Mary Somerset. Of these four couples, three had sons named Solomon. So, by 1790, there were four Solomon Wisemans living in a small area a stone’s throw north of the Thames: a man of sixty-seven; his thirty-seven-year-old son; a fourteen-year-old; and a newborn.

Meanwhile, south of the river, more were multiplying. There were two Wiseman couples within a mile of each other. These couples produced three Solomons between them. In 1790, as well as those four Solomon Wisemans north of the river, there were two more in the south: a boy of thirteen and a newborn. Another Solomon Wiseman, from the same address as the thirteen-year-old, was born in 1768 but died a year later.

To get even to this degree of coherence, I had to kill off wives and make their husbands re-marry. I sent families backwards and forwards across the river. Fathers and uncles gave their own names to sons and nephews, infants died and their names were given to the next child born. I cursed the eighteenth century’s niggardly way with the same few names: Sarah, Catherine, Richard.