(CNN) -- They met in elementary school, began a romance during World War II and married not long afterward. They had a lifelong devotion to each other as husband and wife that lasted nearly 66 years -- and one day earlier this month they died, just 11 hours apart.
Their children call it their "final act of love."
Harold Knapke, 91, and his wife, Ruth, 89, died August 11 at the Versailles Health Care Center nursing home in Russia, Ohio, spokeswoman Teresa Pohlmon said.
Their children said they were nine days short of their 66th wedding anniversary.
"It's consoling to us that they went together," said their daughter, Margaret Knapke. "On one hand it's difficult to lose both parents at once when you didn't see it coming ... but it's very consoling that they got to go together."
According to Margaret, her father's health had been deteriorating more quickly than her mother's for about a year.
"We would ask, 'Why is he still here?'" Margaret said. "And the answer was that he was here for Mom."
"He loved her very dearly. He was extremely loyal. He wanted to be here with her," she added. "He would sleep all day toward the end but when he'd wake the first thing he'd ask is, 'Where's your mother? How's your mother?'"
Margaret said Ruth contracted a rare infection shortly before her death and it was clear she was not going to recover. When Margaret and her siblings told her father the news, she recalled, he took it calmly but they saw a "shift" in him.
Just a few days later, Margaret and one of her sisters noticed that their father appeared to be very ill, she said.
"My sister said, 'It's almost like he's trying to catch up to Mom.'"
Three days later, Harold died, at 7:30 a.m.
"I think he realized what was happening and wanted to pave the way for her," the couple's son, Ted Knapke, said.
After their father died, the Knapke children surrounded their mother -- who was not lucid -- and told her, "Dad's up there waiting. They got the card game going and it's time you got up there. Don't stick around for us," Ted Knapke said.
Ruth Knapke died that night, at 6:30 p.m.
"I think certainly when two people are that close for 66 years you become pretty in sync mentally. So regardless of their state I think they realized it was time," Ted Knapke said.
Ruth and Harold Knapke met when they were students at the same elementary school in Ohio but were separated when Harold's family moved several towns away, according to Carol Romie, another daughter of the Knapkes.
"Dad was a year ahead of Mom and I remember Mom would tell us, 'I had a crush on your dad when I was in the third grade,'" Margaret Knapke said.
It wasn't until Harold was serving in World War II and stationed in Germany that their relationship began. Ruth's brother-in-law Steve, who was also serving, overheard that Harold was from the same county in Ohio as Ruth and suggested that Harold write to her.
Their relationship grew from there, according to their daughter Ginny Reindl.
"Mom knew who he was right away," Margaret Knapke said of her mother's reaction to the letter. The two continued to write each other until Harold returned from the war in 1945.
The couple married two years later, on August 20, 1947, and had six children together: Carol, Pat, Margaret, Ginny, Ted and Tim. Harold worked in Ohio's Fort Recovery school system as a principal, teacher and coach and Ruth became a school secretary.
"I guess to me, the most important part of the story was their dedication to each other -- loyal right to the end," Romie said. "Supportive and protective of each other, and that was the beautiful part. They worked at being married for 65 years. It didn't just happen. They went into it with the idea that this was forever, and it was. They made it that way."
The two were laid to rest together in a joint funeral.
"Mom and Dad were ordinary people," Reindl said. "I guess if people can learn from our story it's that there is love that lasts, and that's a good thing."