What do franciscan monks believe in?

The Order of Friars Minor (the official name of the Franciscan monks) is a mendicant order (meaning they give up all worldly possessions and live as paupers off of public donations) of the Roman Catholic Church.

The Franciscans are actually divided into three different orders:

Observants (commonly called "Franciscan friars"),

Capuchins (named for their "caps" or friars' hoods), and

Conventual Franciscans

All of these orders seek to follow the life of St. Francis of Assisi, from which the Order takes its name. St. Francis is a very important saint to Catholics and to many Protestants. Franciscan monks subject themselves to the Rule of St. Francis, a book written by the saint on how to live a holy and monastic life.

For more, please see http://www.newadvent.org/cathen/06221a.htm

For the short version, http://en.wikipedia.org/wiki/Francis_of_Assisi