There are a number of pitfalls to consider when going from historical beers to present taste. How sweet were the beers? Texts indicate that beer was typically underattenuated. How do you translate archaic measurements and estimate hop bitterness? Do you throw in a portion of smoked malt to replicate the malt-drying fires? Do you allow the beer to sour or serve it fresh?
Don't worry about getting it right though. Just like with Latin pronunciation, no one really knows what the flavor was like.
Scan sites on the Internet for old brewing texts. In addition to eBay, sites like