Ипатьевская летопись
Contemporary written sources about Mindaugas are very scarce. Much what is known about his reign is obtained from the Livonian Rhymed Chronicle and the Hypatian Codex. Both of these chronicles were produced by enemies of Lithuania and thus have anti-Lithuanian bias, particularly the Hypatian Codex. They are also incomplete: both of them lack dates and locations even for the most important events. For example, the Livonian Rhymed Chronicle devoted 125 poetry lines to Mindaugas's coronation, but failed to mention either the date or the location. Other important sources are the papal bulls regarding baptism and coronation of Mindaugas. The Lithuanians did not produce any surviving records themselves, except for a series of acts granting lands to the Livonian Order, but their authenticity is disputed. Due to lack of sources, some important questions regarding Mindaugas and his reign cannot be answered.