You didn't with me I think.... But even in modern English... If you want to say Fred the book is owned by Fred, you get: "Fred
s Book". The s is what remains of a Genitive case, the same s still exists in (Both Old and Modern) Dutch, and in German. It's exists in the Nordic languages (including Old Norse).....
If you're still not convinced, I've got a book about Anglo-Saxon, I'll look it up in there tomorrow
Oh, and since I'm Dutch, and speak quit some German, I'll give a example of both these language's as well.
Now in German the name-cases still exist properly. The Germans generally use an article, only with the Genitive they've got the s in the end as well. The article is Des, and you get an S in the end of the word as well. For example, 'from the father' would be 'des vaters'
Dutch cases are basicly the same as German ones, 1 or 2 Article's are different though, but in Dutch, (for those who speak Dutch) think of the saying 'De heer des huizes', or 's morgens... ('s is shortend for des).
With some quick looking up I'd be able to give you examples of Old Norse and the modern Nordic Languages as well, but I cba