There are multiple pre-medieval historic records documenting existence and history of Kojetín in Czech and Moravian archives.
According to undocumented, but often quoted legends  origins of Kojetín can be traced to the times of Samo's Empire. The town is said to receive its name after Samo's legendary son Kojata, who allegedly defeated Avars at this locality and founded a settlement named Kojata, later Kojetín. Local Czech historians in the past issued various theories about the above and some other "Kojata's" - most prominent being Kojata Všeborovic and Kojata Hrabišic, who was a chaplain in Olomouc in 1223.
Filological and geographical studies have shown that the settlement was probably founded in the 13th century.