It's seen in documents over a long period of time and S sounds are sometimes written as an F or an S that looks like an F. What were the conventions on their uses? And when did it talk put of fashion?
More can be written, but you might like 'Why does the "s" at the beginning of each word in older American and European documents look like an "f"?' by /u/kookingpot, and for when, an indication is in "When did the long 's' begin to go out of ſtyle? Were there any particular reasons for this?" by /u/pratchett2.
This is not to diſcourage diſcußion. More questions, data and debate are welcome.
That letter is not really an f, or pronounced like one. You are referring to what's known as a long, or medial, or descending S. It was used always as the first S or the first S in a pair, so success becomes fuccefs. It looks f-like, but f's are written only above the line, and only the long S was extended below it. It's quite archaic: though you may have run across it in 18th or 17th c. print sources, you can see it throughout this Latin 14th c. medical MS and even this 5th c. MS
The long S has dropped out of current English typography, but it's stuck around in a few other places. If you ever pursue learning calculus, the integral sign is a long S, to stand for the Latin Summa. And if you ever learn German, you'll find that the Germans continued to use something like the long S in the formal typography, Fraktur, into the 20th c. Except that there it looks more like an f. But if you start reading Fraktur you'll be trying to memorize all the inscrutable capitol letters , and so that long S will be the least of your troubles.
And for all of their attention to old forms, for some reason makers of violins, violas, cellos and basses refer to the curvy holes in the soundboards as f-holes, even though they really do more resemble the long S.
