William Cowie was the son of Alexander Cowie and Elizabeth Garden and studied at Eton CollegeTrinity Hall, Cambridge in 1855 where he received his BA.
William Garden Cowie (8 January 1831  26 June 1902) was bishop of the Anglican Diocese of Auckland, New Zealand, from 1870 to 1902. Cowie was born in London, to Alexander Cowie and his wife Elizabeth Garden, daughter of Alexander Garden. Educated at Eton College and Trinity Hall, Cambridge, where he received his BA in 1855 and MA in 1865. Trinity Hall, Cambridge 
