Comment by vintermann

The lower case "e" in gothic cursive often looks like a lower case "r". If you see one of these: ſ maybe you think "ah, I know that one, that's an S!" and yes, it is, but some scribes when writing a capital H makes something that looks a LOT like it. You need context to disambiguate. Think of it as a cryptogram: if you see a certain squiggle in a context where it's clearly an "r", you can assume that the other squiggles that look like that are "r"s too. Familiarity with a scribe's hand is often necessary to disambiguate squiggles, especially in words such as proper names, where linguistic context doesn't help you a lot. And it's often the proper names which are the most interesting part of a document.

But yes, writers can change style too. Mercifully, just like we sometimes use all caps for surnames, so some writers would use antika-style handwriting (i.e. what we use today) for proper names in a document which is otherwise all gothic-style handwriting. But this certainly doesn't happen consistently enough that you can rely on it, and some writers have so messy handwriting that even then, you need context to know what they're doing.