From Medieval News:
Damien Kempf on Tumblr came across this image from a 12th century manuscript known as the Bible of Stephen Harding. This work contains many images, including this page that details the story of King David. Just like a modern day comic book, you are supposed to go through this page from left to write and top to bottom, and read the caption for each box.
Full Story: Medival News: The first ever comic book?
(via Leah Moore)
That does sound like it could be the first comic book, though there are older example of comic strips, such as cave paintings. There’s also this Iranian goblet from around 3192 BC that includes a sequence of images that could well be considered a comic if you consider art to be comics: