Original: Abraham Lincoln ( February 12 , 1809 -- April 15 , 1865 ) was the 16th President of the United States , serving from March 1861 until his assassination in April 1865 .
Simplified: Abraham Lincoln ( February 12 , 1809 - April 15 , 1865 ) was the 16th President of the United States between 1861 and 1865 .