In 2013, the Oxford Dictionaries announced their word of the year to be “selfie”, which they define as “a photograph that one has taken of oneself, typically one taken with a smartphone or webcam and uploaded to a social media website.” The technique is far from being a strictly modern phenomenon though.
Indeed, the photographic self-portrait is surprisingly common in the very early days of photography exploration and invention, when it was often more convenient for the experimenting photographer to act as model as well. In fact, the picture considered by many to be the first photographic portrait ever taken was a "selfie". The image in question was taken in 1839 by an amateur chemist and photography enthusiast from Philadelphia named Robert Cornelius.
Setting up his camera at the back of the family store in Philadelphia, Cornelius took the image by removing the lens cap and then running into frame where he sat for a minute before covering up the lens again. On the back of the image he wrote "The first light Picture ever taken. 1839."