Year 1491 (MCDXCI) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar.

"Medicine man" or "medicine woman" are English terms used to describe traditional healers and spiritual leaders among Native American and other indigenous or aboriginal peoples. Anthropologists tend to prefer the term "shaman," a specific term for a spiritual mediator from the Tungusic peoples of Siberia.

The primary function of these "medicine elders" (who are not always male) is to secure the help of the spirit world, including the Great Spirit (Wakan Tanka in the language of the Lakota Sioux), for the benefit of the entire community.

Sometimes the help sought may be for the sake of healing disease, sometimes it may be for the sake of healing the psyche, sometimes the goal is to promote harmony between human groups or between humans & nature. So the term "medicine man/woman" is not entirely inappropriate, but it greatly oversimplifies and also skews the depiction of the people whose role in society complements that of the chief. These people are not the Native American equivalent of the Chinese "barefoot doctors", herbalists, nor of the emergency medical technicians who ride rescue vehicles.

Leonardo di ser Piero da Vinci (Italian pronunciation: [leoˈnardo da ˈvintʃi]  pronunciation (help·info); April 15, 1452 – May 2, 1519, Old Style) was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist, and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance humanist ideal. Leonardo has often been described as the archetype of the Renaissance Man, a man of "unquenchable curiosity" and "feverishly inventive imagination". He is widely considered to be one of the greatest painters of all time and perhaps the most diversely talented person ever to have lived. According to art historian Helen Gardner, the scope and depth of his interests were without precedent and "his mind and personality seem to us superhuman, the man himself mysterious and remote". Marco Rosci points out, however, that while there is much speculation about Leonardo, his vision of the world is essentially logical rather than mysterious, and that the empirical methods he employed were unusual for his time.