In literature depicting the "romantic" medieval period, the Knight Errant is a common trope. Is there any historical basis for this character type?

by BananaFrappe
J-Force

I answered a very similar question about 2 weeks ago: https://www.reddit.com/r/AskHistorians/comments/9db1dw/the_figure_of_the_knighterrant_is_a_common/