There are officially two flags of Bavaria: the striped type, and the lozenge type, both of which are white and blue. Both flags are historically associated with the royal Bavarian Wittelsbach family, which ruled Bavaria from 1180 to 1918.
Both horizontal and vertical flags with stripes or white and blue lozenges without arms can be considered official for use as state and civil flag and as civil ensign (on lakes and rivers). The variants defaced with the arms are unofficial. However, the de facto civil flag used is in most cases a lozenge-style flag with the arms and a very popular symbol of regional pride used and displayed throughout the state.