For the purposes of this book we are dealing with the Thames between Oxford and London, though as a matter of fact, tradition has it that the Thames proper does not begin until below Oxford, where it is formed by the junction of the Thame and the Isis. Tamese (Thames) means "smooth spreading water." Tam is the same root as occurs in Tamar, etc., and the "es" is the perpetually recurring word for water, e.g., Ouse, ooze, usquebagh. Isis is probably a back formation, from Tamesis. In Drayton's Polyolbion, we have the pretty allegory of the wedding of Thame and Isis, from which union is born the sturdy Thames.