We do not know for certain why Alfred Nobel did not establish a prize in mathematics. There are several theories revolving around his relationship and dislike for Gosta Mittag-Leffler (1846–1927), the leading Swedish mathematician in Nobel’s time. Most likely it never occurred to Nobel or he decided against another prize. The Fields Medal in mathematics is generally considered as prestigious as the Nobel Prize. The Fields Medal was first awarded in 1936. Its full name is now the CRM-Fields-PIMS prize. The 2009 winner was Martin Barlow (1953–) for his work in probability and in the behavior of diffusions on fractals and other disordered media.