Oswald Sydney Wilson Mahon was born in the fourth quarter of 1897 the youngest son of James Joseph Mahon and his wife Mary (née Thomson). His parents were married on the 02nd June 1882 at Emmanuel Church, Everton. James, was a 23 year old cashier of 63 West Derby Road, his father, Robert, was a clerk, whilst Mary was aged 20, of the same address, her father, Samuel, was a foreman. 

The 1901 Census finds the family living at 23 St Domingo Grove, Everton. His father, James J., is aged 40, born in Dublin and is shown to be employed as a ship and insurance brokers agent. He is living with his mother, Mary, who is aged 37 and was born in Scotland. They reside with seven their children recorded as follows; Eveline T. who is aged 17, Lilian G., who is aged 14, James H., who is aged 12, Norman E., who is aged 8, Irene A., who is aged 5, Oswald S. W., who is aged 3, and Muriel D., who is aged 1. There is one servant registered in the house Maggie Barnett aged 27 born in Llangefni, Anglesey. 

The 1911 Census shows the family have moved across the River Mersey and are residing at “Brentwood” 85 Seabank Road, Liscard, Cheshire. His father, James, is aged 51, and is a ship and insurance broker, his mother, Mary, is aged 48. They advised that they had been married for 28 years, and have had 8 children, 7 of whom have survived. There are five children declared in the household; Oswald, is 13 years of age and lives with his parents and four sisters, all of whom are single; Eveline Thompson, is aged 27, Lilian Grace, is aged 24, Irene Alwyn, is aged 15, and Muriel Dorothy, is aged 11. The family again employ a servant; Hannah Thomas a 16 year old from Denbigh. 

Oswald was educated at Liverpool College, and Councilor Wrigley’s Liscard High School; he was also a member of the 1st New Brighton Territorial Cadet Corps part of the Cheshire Regiment. He served in that unit for over four years, and during his last year, was appointed Lieutenant and Adjutant.

Oswald was working with a Cotton Broker in Liverpool prior to enlistment.

It is not certain when he joined the Army, but he was commissioned on his 18th Birthday, as a Second Lieutenant in the 5th Battalion, The King’s Liverpool Regiment. Gazetted on 22nd October 1915. As he did not receive the 1915 Star he crossed to France after December 1915.  At some stage after this he crossed to France and was posted on attachment to the 17th Battalion. This must have been very shortly before the action in which he received his fatal wounds, as he doesn’t appear in the 17th Battalion’s War Diary before this date. The action took place on the 09th April 1917, during the first day of the Battle of Arras. He was attached to ‘B’ Company, which was dug in West of Boiry Copse.

Oswald died of his wounds, five days later on 14th April 1917, aged 19, and now rests at Mont Huon Cemetery in France.

During the First World War, Le Treport was an important hospital centre and by July 1916, the town contained three general hospitals (the 3rd, 16th and 2nd Canadian), No.3 Convalescent Depot and Lady Murray's B.R.C.S. Hospital. The 7th Canadian, 47th and 16th USA General Hospitals arrived later, but all of the hospitals had closed by March 1919. As the original military cemetery at Le Treport filled, it became necessary to use the new site at Mont Huon. There are now 2,128 Commonwealth burials of the First World War in the cemetery and seven from the Second World War. The cemetery also contains more than 200 German war graves. The cemetery was designed by Sir Reginald Blomfield.

CWGC shows him as being attached to the 17th Battalion from the 5th Battalion of The King's Liverpool Regiment.  

An obituary was placed in the Liverpool Daily Post and Mercury, 21st April 1917: 

April 14, died from gunshot wounds received in action, aged 19 years, Second Lieutenant Oswald S. W. Mahon, King’s (Liverpool Regiment), the dearly beloved youngest son of James J. and Mary Mahon, Brentwood, Seabank Road, Wallasey.

The Wallasey News reported his death as follows:

Liscard Lieutenant Dies From Wounds

We regret to record the death of 2nd Lieut. Oswald (Ossie) S.W. Mahon, of the King’s Liverpool Regt., which occurred on April 14, at the General Military Hospital, Le Pleport, France, from gunshot wounds received in action in the big push on Easter Monday. He was only 19 years age, and received his commission on his eighteenth birthday. The brave young soldier, who was educated at the Liverpool College, completed his studies at Councillor Wrigley’s Liscard High School, was held in great esteem as one of the most popular boys of the 1st New Brighton Territorial Cadet Corps. He was over four years in the Corps, and previous to joining the Forces had been Lieutenant and Adjutant for twelve months. He was the youngest son of Mr and Mrs James J. Mahon. “Brentwood,” Seabank Road, Wallasey.

His elder brother, Captain Mahon, was killed in action last September. (Wallasey News). 

Soldiers Effects of £75 7s 9d went to his father, James Joseph, no Pension has been record found. 

Oswald is commemorated on the Cotton Association Memorial now situated within Walker House, Exchange Flags, Liverpool.

The brother referred to in the Wallasey News article was Ossie's brother James H. He was a Captain in the 8th Battalion of The King's Liverpool Regiment. He was killed on 16th September 1916, aged 28, and he now rests at La Neuville British Cemetery, Corbie. 

His death was reported in the Liverpool Daily Post on Saturday 23rd September 1916; 

We currently have no further information on Oswald Sydney Wilson Mahon. If you have or know someone who may be able to add to the history of this soldier, please contact us.