When I first began toying with the idea of writing a new historical mystery series based around a woman who had served in the British Secret Service during the Great War, I was concerned I wouldn’t find much factual basis to craft my heroine from. But that couldn’t have been further from the truth.

Careful digging brought to light the thousands of women who went to work for the various intelligence gathering agencies in Britain during World War I. They served at the headquarters in London, in various field offices across the globe, and even behind enemy lines in the German-occupied areas as part of several intelligence gathering networks connected with the British War Office. These brave women served with great distinction and with utmost secrecy, and many of their contributions are still widely unknown.

Within Britain, women were employed by the Directorate of Military Operations (DMI), as well as the intelligence sections of the Foreign Office, Admiralty, and Army. They operated as secretaries, typists, clerks, translators, messengers, historians, switchboard operators, supervisors, and more. More specifically, they worked in postal censorship, helped draft propaganda, and designed paperwork networks for tracking spies and foreign intelligence.

In fact, one division of the DMI was staffed almost exclusively by women. MI5, the branch in charge of counterespionage, maintained a massive registry of suspects and information regarding foreigners within the UK and any British citizens with ties to the enemy, no matter how seemingly insignificant. This massive undertaking was staffed by more than six-hundred well-educated women.

In Room 40 of the Old Admiralty Building, where many of the cryptographers worked during the war for Naval Intelligence, they performed secretarial tasks and even assisting with decoding. While in the foreign division of the DMI—a division which would eventually morph into MI6—women served as clerks, typists, and translators—organizing information and helping draw connections between seemingly disparate data. Some of these women were also sent abroad to help staff the espionage sections of British offices in neutral and allied countries. It was as part of this foreign division that I decided my fictional heroine, Verity Kent, had served during the war.

Another distinction that set these positions apart from other work open to women during the war was the fact that many of these intelligence-gathering organizations employed married women, where other war-time agencies would not. Women in intelligence operations were also paid more than other positions, though by no means at an equal rate to their male counterparts, despite undertaking many of the same risks.

Learning about these female operatives left me with a burning desire to make their incredible contributions known. Like Verity, these women were intelligent, highly capable, adventurous, and intrepid. They felt compelled to do their part to help Britain win the war—whatever that part may be—and bring as many of their soldiers home safely as possible. They threw their all into every challenge they faced, fiercely guarding their secrets, even keeping the truth about the true role they played from family and spouses.

And all the while they watched the death tolls mount, losing countless friends and loved ones. They were under the same tremendous strain as the rest of the country, and yet they stifled their grief and continued to serve for the sake of the living. It’s partly this juxtaposition of strength and vulnerability that makes them so fascinating.

There has been a recent surge of interest in women who served in wartime positions traditionally thought of as belonging to men. I think this is because women are tired of hearing that their contributions to history don’t matter, of being told to stop pushing ourselves forward and sit quietly in the background. We’re tired of letting men write the history books. Instinctively, we know we’ve always been there somewhere in the annals of the past, hidden in the spaces between paragraphs of men’s exploits, because whenever conflict or crises arise, women always step forward to do their bit, to contribute whatever is needed. It’s been the same for time immortal. And we want to know how women in the past have filled those voids and positions. We want to learn from them and honor them, to feel pride in their accomplishments. We’re no longer content for them to be forced to dwell in the cracks of history when they can serve as inspiration to us all.

This article first appeared at Between the Chapters.