mathias walter day was the second of seven children of mathias day (the founder of daytona beach, florida) and mary blymyer, both native ohioans. he was accepted to the united states military academy at west point in 1873. a graduate of the class of 1877 alongside henry ossian flipper, the first african-american to graduate from west point, day was popular with his classmates, but was "ranked close enough to the bottom to be assigned to a black regiment".