It stands alone next to the main block of text on the right-hand side of the page and looks like a capital J. But it’s not a letter, it represents the number 1. It’s the first printed page number. It can be found in a sermon by a Carthusian monk from Cologne from 1470. The slightly smudged sign has a major appearance in Dennis Duncan’s book “Index, Eine Geschichte des”. Because it marks a historical turning point. Book printing was still young, less than 20 years old, but the process of standardization was already picking up speed: the book pages became stable, the pagination could be integrated into a reliable navigation system. If you were looking for a specific passage in a book and knew the number of pages, you would not leaf through the pages roughly, but rather pointedly to an exact location.
Dennis Duncan: “Index, a history of. Of searching and finding”. – Culture
