The First Epistle of John, often referred to as First John, is the fourth epistle attributed to John the Evangelist (believed to be the author of the Gospel of John, and the other two Epistles of John).  The First Epistle of John was probably written in Ephesus sometime around 100 AD when John was in his later years of life.  Although the author does not identify himself, he notes that he was one of the inner circle of three disciples (James, John, and Peter) and describes himself as the disciple whom Jesus loved.  Authorship was confirmed by Irenaeus (130 AD, one of the first Christian theologians) who noted that John was the author of the gospel.  It was written to counter docetism, which is the belief that Jesus did not come “in the flesh” but only as a spirit.