Wikipedia says that Schwarz (b. 1843) marrid Kummer in 1912 at the age of 69, had six children, then died in 1921 at the age of 78. I'm surprised (not against!).
According to https://sprague.one-name.net/getperson.php?personID=I447193&tree=Sprague , their first child was born 1862, last child 1883, but again marriage 1912. The source includes wikipedia.
I think something could be wrong with this data. So is there another source independent of Wikipedia?