Simplify the following text for a Grade 8 native English-speaking person.
Original: The only known and confirmed photograph of Lincoln at Gettysburg , taken by photographer David Bachrach was identified in the Mathew Brady collection of photographic plates in the National Archives and Records Administration in 1952 .
Simplified: The only known and confirmed photograph of Lincoln at Gettysburg was taken by David Bachrach . It was identified in the Mathew Brady collection of photographic plates in 1952 .