That's not a medieval hand; that's later, likely Early Modern. (One way you can tell is that the main text is printed). You might post in reddit/r/paleography and see if you can get a confident reading. That 1598 is probably the date.
I'm going to guess (emphasis on guess) that this is a Latinized version of a name, probably English, probably the owner of the book. The first word could well be the abbreviated version of a Latinized first name; that would be my bet. I'm not confident enough to guess what it is. The last two words look like they might be something like "Franciscus Boswellus (??????)," i.e. "Francis Boswell," i.e., the last part of someone's name. I'm a medievalist, not an Early Modernist, so I don't know. But someone who works on 16th c texts could probably clear this up for you in a hurry.
If you find out more you should come back and tell us!