Magnus Fea was one of possibly three children of John Brooke Fea and Florence Maud Gunn. He was born on 29th Jun 1874 in Rosario, Argentina.

Magnus and his sister Florence were in Cottingham, Yorkshire with his aunt Cecilia Fea in 1881 and Magnus a boarder at a school in Repton, Burton on Trent, Derbyshire in 1891.

He married Inez Clare Blagden (b. abt 1875) at San Salvador, Belgrano, Argentina on 1st June 1899. Inez was the daughter of broker Joseph Blagden. Magnus is stated to be living in Buenos Aires and Inez in Belgrano, Argentina at the time. His occupation is given as "estanciero", an owner of land in the Pampas (grasslands). The witnesses were J Blagden, George Lumsdaine and Kathleen Cecilia Fea. Kathleen was Magnus's sister and married George Lumsdaine, later that year.

They are known to have had at least two daughters:

• Violet Florence Fea b. 17th June 1902 in Argentina. She and her sister appear in the 1911 census with their aunt, Florence Elsie Fea in Dorchester, Dorset. Violet married Oswald Emerson Chapman (b. 27th September 1899 on 5th September 1928 at Wareham, Dorset. Oswald died in Devon in 1975 and Violet in 1990.

• Clare Brenda Fea b. abt. 1903 in Argentina who married William Hugh Skinner (b. 1893) in Lahore, Bengal, India in 1931. Hugh was the son of William Skinner.

Some of the family appear on a passenger list for the "Aragon", which sailed from Buenos Aires and arrived in Southampton on 20th July 1907. Magnus is stated to be accompanied by adults John Fea and Florence Fea and daughters Brenda and Violet. John and Florence would have been Magnus's parents. There is no mention of his wife.

Magnus died at Bridport, Dorset in the following year at the age of thirty four.