|Marlene A. Eilers Koenig collection|
Heinrich was the last male member of the Reuss-Schleiz, younger line. He was born on May 13, 1895, the only son of Heinrich XXVII, Prince Reuss (Younger Line) and Princess Elise of Hohenlohe-Langenburg, a granddaughter of Princess Feodora of Leiningen (Queen Victoria's half sister).
Hereditary Prince Heinrich was the youngest child of Prince Heinrich XXVII and Princess Elise. He had two older sisters, Viktoria 1889-1918) who married Duke Adof Friedrich of Mecklenburg-Schwerin in 1918, Luise (1890-1951) and two brothers, Heinrich XL (1891-1891) and Heinrich XLIII (1893-1912.)
He succeeded his father in 1928, and became head of the House of Reuss following the merger of the Younger and Elder Lines, when the Elder line became in extinct in 1927.
He adopted a cousin, Prince Heinrich I, a member of the Köstritz branch of the family, who was married to his niece, Duchess Woizlawa Feodora of Mecklenburg.
Heinrich XLV joined the Nazi party in the 1930s. He was arrested by Soviet military officials at his home in Ebersdorf in August 1945, and was never seen again. It is assumed that he was killed in a NKVD special camp in Buchenwald. He was declared officially dead on January 5, 1962.
He never married, and he was succeeded as head of the house by Prince Heinrich IV of the Köstritz branch.