"My Other Mother" Mother's Day Card, 1921

Mother's Day, a national holiday devoted to mothers, was first officially recognized in 1914. In the years that followed, presenting mothers - and other beloved family members or friends - with greeting cards on the second Sunday of May became a popular tradition. This Mother's Day card for the unknown sender's "other mother" was mailed to a 71-year-old Akron, Ohio, widow in 1921.