You will be given a context, a subject and a relation. Your task is to generate a question based on the subject and relation. The generated question should include the given subject. Try to use a minimum number of words that are not present in either context, subject or relation while generating question.
Q: Context : Henry Percy Douglas was born at Dacre Hill, Higher Bebington, Cheshire, on 1 November 1876, the second son of Admiral Sholto Douglas (1833--1913) and his first wife, Maria Louisa, the only daughter of William Bickford, of Stonehouse, Devon.
Subject : Percy Douglas
Relation : military branch
A:
In what military branch did Percy Douglas serve?