The birth of native Estonian literature was in 1810 to 1820 when the patriotic and philosophical poems by Kristjan Jaak Peterson were published. Peterson, who was the first student at the then German-language University of Dorpat to acknowledge his Estonian origin, is commonly regarded as a herald of Estonian national literature and considered the founder of modern Estonian poetry. His birthday on March 14 is celebrated in Estonia as the Mother Tongue Day. A fragment from Peterson's poem "Kuu" expresses the claim reestablishing the birthright of the Estonian language: