When Hindu-Arabic numerals were introduced by [[Fibonnaci]], it took 300 years for them to be adopted. Church authorities in medieval Europe viewed them with suspicion, saying that they could be altered too easily compared to Roman numerals. Roman numerals would not be dropped until the 1500s. The last arithmetic book to use Roman numerals appeared in 1514. The Medici bank did not use Hindu-Arabic numerals exclusively until 1500. In 1520, the German town of Freiburg refused to recognise financial documents unless they used Roman numerals or were written out in words. Scotland was using Roman numerals as late as the 17th century. --- **Source** Gleeson-White, Jane. Double Entry: How the Merchants of Venice Created Modern Finance. New York: W.W. Norton & Co., 2012. http://www.myilibrary.com?id=336325.