Peter Mednis was born in Russia on 9th October 1890, and was a Russian citizen. He had been living in New Zealand for four years at the time of his enlistment and was employed as a watersider on the Auckland waterfront. He left New Zealand for the UK on 14 July 1917 and by late October left Sling Camp for France where he joined the 6th Coy, 3rd Battalion, Auckland Infantry Regiment. In early 1918 he spent two weeks with the first Australian Tunnelling Corps and was then detached to the XXII Corps Reinforcements, and was serving with that unit when on 18th February 1918 he was killed in action in Belgium. He has no known grave and his name is listed on the Buttes New British Cemetery (NZ) Memorial, Polygon Wood, Zonnebeke, West-Vlaanderen, Belgium.

Following Peter's death efforts to contact his executor in Riga, Russia, were unsuccessful, and his alternative next of kin, a friend living in Hamilton was no longer alive. Consequently his medals were among those forwarded to the Town Clerk, Auckland City Council, and later presented to the Auckland War Memorial Museum.

Note: On his attestation form Peter Mednis gave his name as Peter Edward Thomson, although his name was also recorded as Peter Mednis and this became the name used on his Service Record..