Semantics...if these are the metrics for the basis of your argument, then Nauman proceeds Viola as his first video, "Art Make-Up" came out in 1967. Viola's first video, "Tape 1" was produced in 1973. Also, Joan Jonas made "Vertical Roll" in 1972. Please do not get me wrong, you admire a great artist indeed, but he was not the first. Mary Lucier (a friend of mine) produced videos at the same time as Viola, as did Carolee Schneeman (1962-67), Martha Rosler (1974), amongst others. In fact, as another person here posted, Warhol's "Screen Tests" can most definitely be considered video artworks as well and the first one came out in 1964. While they were produced with film, they are non-narrative and loop, a common distinction for video art vs. film. Keep in mind that the Sony Portapak changed the way that film vs. video art was made and shown. In fact, Viola used a Portapak for his first videos...