Half a mile northwest of Clerkenwell Green was a place where the fledgling Fleet ran, for a short distance, parallel to the road to Hampstead. Between road and river the ground was low, and shiny with shifting sheets of water. But on the opposite bank, nearer to Clerkenwell, the ground was firm enough that shrubs and vegetables could be planted in it without drowning, and buildings set on it without sinking into the muck. A hamlet had gradually formed there, called Black Mary’s Hole.