A soldier sent a letter to his mom in 1945. It was just delivered.

“Hi, was your husband in the service?” Ms. Gonsalves, 89, recalled the letter carrier’s saying. “Yes, he was,” she answered. “But I didn’t know him then.”

The letter carrier handed her an envelope. “Well, I’m pretty sure I have something that’s personal for you,” he said.

Inside the envelope was an unopened airmail letter that her husband, John A. Gonsalves, had sent to his mother in Woburn, Mass., when he was a 22-year-old Army sergeant serving in Germany just after the end of World War II.