In the early years of World War I, Zeppelin air raids over Britain saw relative success, as the incendiary bullets and fighter aircraft which doomed them were not yet commonplace. While only 557 people in total died from the raids, their initial invulnerability left the British public terrified. As an island, the wars of continental Europe seldom reached their shores, and now their own homes were at risk of being destroyed by the enemy. As The Atlantic reports, this forced them to abandon their homes for shelter once the alarm was raised, leaving their previously private attire exposed to their neighbors. 

Pajamas presented a more practical and fashionable form of nightwear for both men and women, as the pockets and thicker material were more useful than the thin fabric of more conventional nightclothes (via BBC). According to Oxford, pajamas (as well as the work clothes women in factories often used) also upended views on women wearing pants; something that before the war would have been shunned. Both two-piece and onesie-like outfits were commonplace during the war, and while they somewhat fell out of favor afterward, the standard for what we wear to bed had been set. 

ncG1vNJzZmivp6x7qL7Up56eZpOkunCAlG1ucG1fqbWmecGisZqqopp6s7HArKanZaestrR52Z6nqZ2cnrturs6mm6ilkZ67oIPSZqeoqKWhrrO12Z6bZqiRn66urdJo