Question: Which event in Edgar Allan Poe's life has remained mysterious, prior to which became engaged to Sarah Elmira Royster Shelton, and was soon found delirious in Baltimore and in need of assistance?
Sentence (from "John P. Poe Sr."): John Prentiss Poe Sr. (August 22, 1836 – October 14, 1909) was Attorney General of the State of Maryland from 1891 to 1895.
Relevant evidence: No