1910s

At some point during the second decade of the 20th century, the 1910s, two English schoolboys, Millington and Judson, became friends. The former reached the rank of Commodore in the British Navy, and the latter beaome a brilliant professor in advanced mathematics. Despite many years of friendship, their relationship became bitter when both were assigned to work at a base in Maiden's Point during World War II. (TV: The Curse of Fenric)
It was also the decade of the First World War. (TV: The War Games)
Eustacius Jericho was born at some point in the 1910s, a decade after his future self from 1967 had been marooned for three years. (TV: Survivors of the Flux)