The author was born Edgar Poe and the middle name was added by Frances and John Allan, who took in the orphaned child but never adopted him legally. (Edgar Allan Poe Society of Baltimore - General Topics - Poe’s Middle Name).
|John Allan's marker between his first wife, Frances Valentine Allan (right) and Louisa Allan (left).|
In England the personal name is usually spelled Alan, the surname Allen; in Scotland the surname is more often Allan.
It's interesting to note the size of the markers. Frances Allan’s tombstone is much smaller and shorter than the markers for John Allan and Louisa Allan. At the time, the husband was considered the head of the household, and his decisions were mostly unquestioned. There was a family hierarchy and we often see this in the size and height of gravestones. The second Mrs. Allan’s grave is the same size and stature (actually, it looks a little bit larger in this picture) of her husband’s, most likely because she outlived him by decades.