The Wagner literature contains references to Mathilde Wesendonk and to
Mathilde Wesendonck, more or less evenly distributed. Otto and Mathilde
actually used the spelling, Wesendonck, one that also appears on the
title pages of Mathilde's published works; but their eldest surviving
son called himself Franz von Wesendonk. The title of Wolfgang Golther's
edition of the correspondence between Wagner and Mathilde is, 'Richard
Wagner an Mathilde Wesendonk'. Wagner's 'Fünf Gedichte für eine
Frauenstimme' (WWV 91) is usually known as the 'Wesendonck-Lieder'. The
family villa in Zürich, which now houses the Museum Rietberg, is known
as the Villa Wesendonck.