If youre in need of 100% historically accurate first names, well here you go! Ive compiled 10s of thousands of medieval names! The only things that arent medieval are the surnames, and we will get to why in a moment.

Under each country, the columns go in order from Masculine names, Feminine names, Surnames.
Put the two numbers into an RNG
Scroll to that number and there you go!

The reason all surnames are modern is due to the difference in nature between surnames and given names. Given names vary person to person, so as eras change you can easily just name babies different names, but surnames belong to many peoples, and change over time. So what I've done is save you the effort of having to memorize when Smythe changes to Smith!