"Any wise and learned Christian or German scholar acknowledges the the true original faith received from Sinai through the hands of Moses was preserved by the Karaites. As an example, in 1641 the German scholar Rittangel visited Troki and [displayed] his warm regard for Karaism, and intently sudied their books and visited many locations where they dwell. He praised their faith in the works which he wrote in those communities. His memory ought to ascend for good before the Lord!"
Back to the Haggadah. Although not the first Latin translation of the Haggadah (see here for the 1512 book which gets that honor, which was translated by a converted Jew) this one is far more interesting. Actually, the 1512 one is interesting too, so before I continue about Rittangel, here is the final page with the traditional prayer for "Anno futuro in hierusalem."
Without a doubt what makes Rittangel's Haggadah so interesting is that he included musical notation for two songs! (Modern notation can be found in the Jewish Encyclopedia as in, e.g., here.)
If anyone wants to break out the harpsichord and upload a recording, be my guest.
The Haggadah is also a good source if you wish to impress or annoy your family by, for example, singing Chad Gadya in Latin ("Unum hoedulum, unum hoedulum"). The Latin price of little kids is duobus solidis, by the way. And if you really want to annoy people, you can introduce the Birkhat Hamazon in Latin (if Yiddish, why not Latin?):
Finally, here is a piece of a letter of his which he sent to John Selden, and which was published, transcribed, translated and annotated by Daniel Lasker in "Karaism and Christian Hebraism: A New Document" Renaissance Quarterly, Vol. 59, No. 4 (Winter 2006), pp. 1089-1116.
"The Karaites [scholars] have had a good name for 1900 years or more. They girded their strength to propound true Scriptural *interpretations; they did not follow the way of the vipers, and did not interpet using letter permutations and gematriot of the *Pharisees. Rather only in God's Torah did they desire, and with straight and clear writings, as I have seen in many of their works."
Lasker printed the entire letter, and the next page continues to say that these works are in manuscript "בכתב מטושטש" which Lasker wisely realizes means "cursive writing," not messy. I think it would have puzzled me.
It is important to note that perushim means both explanations and Pharisees, and Rittangel is obviously punning. He of course also used the term nechashim/ vipers alluding to Matthew 3:7.