Analysis of information sources in references of the Wikipedia article "Donatus, Landgrave of Hesse" in English language version.
The first two branches united in 1997 of the result of the last prince and princess of Hesse-Darmstadt, who were childless, adopting the current head of the house of Hesse-Cassel, Landgrave Moritz. This took place in 1960, and the death of Margaret ("Peg") von Hessen-Darmstadt in 1997 (Ludwig died in 1968) left Landgrave Moritz as the head of both houses.
