Julia Parsons, of Forest Hills, helped win World War II. The secret, invisible war fought behind the battlefields.

Parsons helped break the Germans’ naval codes, often locating the precise locations and plans of their fearsome U-Boat (submarine) fleet, whose Wolfpack swarms threatened to cut off the shipping lanes that connected the U.S. to England.

Parsons only started talking about her wartime experiences in 1997, taking her mission of secrecy to heart. Not even her husband knew what she did during the war.

On Tuesday, she turned 100. There was a parade (featuring local first responders, veterans and civilians) past her home in Forest Hills, and a Zoom party, during where she talked about her long life and wartime experiences. The fête is organized by the Pittsburgh-based nonprofit, Veterans Breakfast Club, which collects and preserves the stories of veterans — and has provided a crucial sense of connection for Parsons.

Parsons’ group of codebreakers at the Naval Communications Annex (part of the former Mount Vernon Seminary) in Washington, D.C.

NEXTpittsburgh caught up with Parsons, who was born in Oakland, grew up in Forest Hills and graduated from Carnegie Tech. She joined the WAVES (Women Accepted for Volunteer Emergency Service) military unit and ended up in a naval facility in Washington, D.C.

“They came through and wondered if anybody knew German and I raised my hand. I said, ‘Well, I had two years of it in high school.’”

That was enough for the Navy. She studied cryptology at the United States Naval Reserve Midshipmen’s School at Smith College and then she was sent to Washington, D.C. for top-secret duty.

“It was decoding the radio traffic between the high command in Germany and the submarines themselves,” explains Parsons. “They sent many, many messages every day. They radioed back and forth all the time.”

The Germans had the Enigma machine, which they assumed made their radio transmissions impossible to decipher. But Polish and British scientists led by the legendary Alan Turing worked on it, eventually developing crucial electro-mechanical devices called bombes (and the world’s first real computer, Colossus) to crack German codes. When Americans entered the war, they developed bombes of their own.

Parsons was so successful that she gained intimate knowledge of German crewmen’s lives, particularly of their more successful and deadly captains.

“We got to know some of these skippers by name, because they had been around so long,” says Parsons.

It was hard work — the Germans changed their codes constantly — and an abstract, mathematical challenge, but real lives were at stake. If the convoys of ships were destroyed, the war effort — and even Britain’s food supply — would crumble.

“Our only goal of course was to sink the submarines,” she recalls. “I wasn’t thinking about the poor souls aboard them. But then, I guess you don’t in wartime.”

Julia Parsons.

“At that point, many, many friends of mine had already been killed. It was a brutal war. Certainly, it still bothers me. We lived in Europe for some years and every time we went into Germany, I kept thinking, ‘Yeah, I could have helped wipe out some of the family members of these people.’”

Parsons and her co-workers didn’t break the codes every day. She feels like she saved the lives of a lot of Allied sailors, though, as messages were decoded and ships were rerouted away from prowling U-Boats.

“They said we did; at least I hope that we did,” says Parsons. “I had two friends from college who were sunk on the submarines and never heard from again. It must be a horrible death. Yeah, I can’t imagine anyone even wanting to go into a submarine.”

Her office was a strange place, surrounded by odd machines, never seen before by anyone but their inventors.

“Many, many computers were lined up along the walls,” recalls Parsons. “They made a horrible noise. And they were very difficult to work.”

Her roommate was cracking Japanese codes, but they never talked about it.

They took painstaking care to make sure that the Germans didn’t know that the Allies had cracked their codes. Admiral Karl Dönitz, who was in charge of the German Navy, had no idea.

“I think on his deathbed, they said that he still was denying that his code could be read,” says Parsons.

German sub crews, however, had their suspicions.