The Legation Quarter lay within the heart of Peking, close to the Forbidden City. It contained a host of foreign embassies within a square mile of land controlled exclusively by its occupants. Chinese nationals were excluded, unless possessing a pass. Guarded, gated, and surrounded by protective glacis, by 1937 the Legation Quarter formed a town in itself, from which many foreigners seldom strayed.
The scale of the security of the Legation Quarter had been a response to the Boxer Rebellion of 1900. The Boxers were proto-nationalist group determined on the elimination of foreign influence within China. They slaughtered thousands of missionaries and their converts.
Peking's foreign community were then besieged within the then unprotected Legation Quarter. Surrounded, they defended themselves against thousands of Boxers, until a multi-national foreign army fought its way from the coast to rescue them. Survival had been a close run thing.
The Boxer siege was still an event in living memory for some of the foreigners in 1937 Peking.