Simplify the following text for a Grade 10 native English-speaking person.
Original: During his appearance at the Norse-American Centennial in 1925 , President Calvin Coolidge gave recognition to Leif Erikson as the Discoverer of America due to research by Norwegian-American scholars such as Knut Gjerset and Ludvig Hektoen .
Simplified: In 1925 , American President Calvin Coolidge recognized Leif Erikson as the Discoverer of America . This was due to research by Norwegian-American scholars such as Knut Gjerset and Ludvig Hektoen .