Reader Alec wrote in to say, “I’d like to know the origin of Kilroy was here, with the man looking over a fence. I saw this all over Germany as an Army dependent in 1954. Does it originate in WWII?”

Maybe you’ve bumped into Kilroy. He’s a bald (or balding) gentleman with a big nose, drawn peeking over a wall. Next to him is usually the phrase “Kilroy was here.” He can be found all over the world, and went viral long before social media or the Internet were around, finding his way through the theaters of war with American troops during World War II. (One of his most daring appearances may have been at the Potsdam Conference in 1945. During the summit, Harry Truman, Winston Churchill and Joseph Stalin had exclusive use of a VIP bathroom. One day, Stalin reportedly used the facilities, and came out demanding to know from one of his aides who Kilroy was, having found the drawing on one of the walls.)

Kilroy doesn’t appear to have originated entirely with U.S. servicemen, though. A similar doodle, known as Mr. Chad, was scrawled throughout Britain as a comment on shortages and rations during the war. Chad was similar in appearance to Kilroy, but was accompanied by a different message: “Wot? No tea?” (or whatever other goods were in short supply at the moment). Chad predates Kilroy by a few years, and may have been the created by British cartoonist George Chatterton in the late 1930s.

As best as anyone can tell, at some point during the war, American soldiers borrowed Mr. Chad’s image and married it to their own name and phrase, “Kilroy was here.”

If the man in the drawing was a variation of Mr. Chad, then where did the name Kilroy come from? While the Oxford English Dictionary writes Kilroy off as a mythical person, dozen of real people claimed to be the doodle’s namesake in 1946, when the American Transit Association (ATA) held a radio contest to establish the origin of the phrase. One of them was James J. Kilroy, who worked as at the Bethlehem Steel shipyard in Quincy, Massachusetts during the war inspecting the work done by others on the tanks and hulls of warships.

As Kilroy explained to the ATA:

I started my new job with enthusiasm, carefully surveying every inner bottom and tank before issuing a contract. I was thoroughly upset to find that practically every test leader [the head of a work crew] I met wanted me to go down and look over his job with him, and, when I explained to him that I had already checked the job and could not spare the time to crawl through one of those tanks again, he would accuse me of not having looked the job over. I was getting sick of of being accused of not looking the jobs over and one day as I came through the manhole of a tank i had just surveyed, I angrily marked with yellow crayon on the tank top, where the tester could see it, 'Kilroy was here.' The following day, a test gang leader approached me with a grin on his face and said, ‘I see you looked my job over.' I nodded in agreement.

Kilroy provided the ATA with corroborating statements from men he worked with at the shipyard, and said that he assumed that shipyard workers who had seen his mark and then joined the military took the phrase with them and began writing it in Europe.

He won the contest and the grand prize, a full-size trolley street car. Just a few days before Christmas, the 12-ton car was delivered to Kilroy’s home in Halifax, MA, where it was attached to the house and used as living space for six of his nine children.