 He was thought to have invented the decimal fractions until the middle of the 20th century, but researchers later discovered that decimal fractions were already introduced by the medieval Islamic scholar al-Uqlidisi in a book written in 952.Moreover, a systematic development of decimal fractions was given well before Stevin in the book "Miftah al-Hisab" written in 1427 by Al-Kashi.His contemporaries were most struck by his invention of a so-called land yacht, a carriage with sails, of which a model was preserved in Scheveningen until 1802.