House of Hesse
On 28 May 1940, Philipp succeeded his father as Head of the Electoral House of Hesse. In 1968, upon the death of his distant agnatic relative, Prince Louis of Hesse and by Rhine (who was also his second cousin as Philipp's mother and Louis' father were grandchildren of Queen Victoria), Philipp succeeded to the total headship of the entire House of Hesse, including grand ducal Hesse (Hesse and by Rhine/Hesse-Darmstadt). Louis had nominally adopted Philipp's son Moritz, who at that time inherited the Hessian and by-Rhine properties, including remarkable cultural collections: for the first time since the division of Hesse into branches after the death of Philip the Magnanimous in 1567, all the branches of the house of Hesse were reunited again.