In 1669, he sold Homburg to his younger brother George Christian, but retained Bingenheim (Landgrave of Hesse-Homburg-Bingenheim).

George Christian died without heirs, and their youngest brother succeeded as Frederick II, Landgrave of Hesse-Homburg.

In Darmstadt on 21 April 1650 William Christoph married firstly Princess Sophia Eleonore, daughter of George II, Landgrave of Hesse-Darmstadt.

They had 13 children, but only four survived infancy:[1] In Lübeck on 2 April 1665 William Christoph married secondly Princess Anna Elisabeth of Saxe-Lauenburg, a daughter of Duke Augustus of Saxe-Lauenburg.

In 1672 they were divorced and Anna Elisabeth retired to and later died in Philippseck Castle in today's Butzbach.