A legend (Latin, legenda, "things to be read") is a narrative of human actions that are perceived both by teller and listeners to take place within human history and to possess certain qualities that give the tale verisimilitude. Legend, for its active and passive participants includes no happenings that are outside the realm of "possibility", as that is defined by a highly flexible set of parameters, which may include miracles that are perceived as actually having happened within the specific tradition of indoctrination where the legend arises, and within which tradition it may be transformed over time, in order to keep it fresh and vital, and realistic. Many legends operate within the realm of uncertainty, never being entirely believed by the participants, but also never being resolutely doubted.The Brothers Grimm defined legend as folktale historically grounded. A modern folklorist's professional definition of legend was proposed by Timothy R. Tangherlini in 1990:Legend, typically, is a short (mono-) episodic, traditional, highly ecotypified historicized narrative performed in a conversational mode, reflecting on a psychological level a symbolic representation of folk belief and collective experiences and serving as a reaffirmation of commonly held values of the group to whose tradition it belongs."