A personal note penned by Prince Philip days before his death to his nephew about his sister's German hunting lodge home has been revealed. Before his death in April, the Duke of Edinburgh was working on a book about his family's ancestral home – a mark of enduring devotion to his European relatives. Prince Philip had completed an elegantly constructed foreword to a history of Wolfsgarten researched and written by Prince Rainer of Hesse, the son of his sister Sophie who had lived at the country estate. His words arrived an hour before news of his death reached the extended family and were revealed in a German documentary, which aired earlier this year.