Wanradt-Koell Catechism

"Wanradt-Koell Catechism" (Wanradti ja Koelli katekismus) is a partly preserved book, which is considered as the oldest printed source of Estonian language, as the oldest known examples of written Estonian originate in 13th-century chronicles. The book is compiled by clergymen Simon Wanradt and Johann Koell. The book was published in 1535 in Wittenberg.

Book's excerpts was discovered in 1929 by historian Hellmuth Weiss.