Who wrote the hymn blessed assurance?

I believe the song was composed as a song- by the Blind hymnist Fannie Crosbie ( died l9l5) she was one of the most prolific hymnists. It should be noted that the song is customarily sung as a tune to the tune of the Steven Foster classic folk song-Beautiful Dreamer, so in a sense it"s a parody. sadly the chorus- This is my story, this is my song, praising the Savior all the day long... was transformed into (this is my Rifle, this is my Gun!, (nuff said) so it goes of parodies there is no end.