Simplify the following text for a Grade 12 native English-speaking person.
Original: Stephanus Johannes Paulus Kruger ( 10 October 1825 â `` 14 July 1904 ) , better known as Paul Kruger and affectionately known as Uncle Paul ( Afrikaans : `` Oom Paul '' ) was State President of the South African Republic ( Transvaal ) .
Simplified: Stephanus Johannes Paulus Kruger ( or just Paul Kruger ) ( 10 October 1825 â `` 14 July 1904 ) was the president of the Transvaal Republic ( South African Republic ) from 1880 to 1900 .