The word "selfie" may be a 21st-century invention, but self-portraits go back to the beginning of photography. Metal plater and amateur chemist Robert Cornelius was mentioned in The Wonderful World of Early Photography as the one who took the first human photographic portrait in 1839 using the new daguerreotype method -and it was a portrait of himself.
Cornelius had set his camera up at the back of the family store in Philadelphia. He took the image by removing the lens cap and then running in to frame where he sat for a minute before covering up the lens again. On the back he wrote “The first light Picture ever taken. 1839.”
Advances in photography that led to shorter exposure times made this simple method of taking a selfie pretty much impossible until the development of the timer. -via Open Culture