Mother's Day has been observed since the 1780s as Mothering Sunday in Great Britain and later America as a day to "Go A'mothering". These days, among others, were observed long before the Hallmark Company was founded in 1910. The Hallmark corporation maintains that it "can't take credit for creating holidays."
While it began as a political antiwar effort and a celebration of moms, Mother's Day quickly became a “Hallmark Holiday” — the company released its first Mother's Day cards in the 1920s.