Congress passed the law designating the second Sunday in May as Mother’s Day on May 8, 1914. The measure formalized the date that became the standard American observance.
The law followed years of campaigning by Anna Jarvis, who wanted a day honoring mothers and their personal sacrifices. Earlier observances had included the 1908 service in Grafton, West Virginia, and a large ceremony at Wanamaker’s in Philadelphia. West Virginia officially recognized the holiday in 1910, and other states soon followed.
The 1914 law did not simply create a fixed calendar date such as May 8 every year. Instead, it designated a recurring weekday pattern: the second Sunday in May. President Woodrow Wilson issued a proclamation the next day, May 9, calling on Americans to display the flag in honor of mothers whose sons had died in war.
That distinction explains a common quiz trap. May 8 was the date Congress acted in 1914; the holiday itself shifts from year to year because it is tied to the second Sunday in May.