He is the only Estonian pre-Crusade ruler, about whom some biographical information is known (he is mentioned only in the Livonian Chronicle of Henry).

[1] Lembitu, also referred to in Latin as Lambite, Lembito or Lembitus, was first mentioned in chronicles in 1211.

Lembitu attempted to unite the Estonians in order to withstand the German conquest.

He managed to assemble an army of 6,000 Estonian men from different counties, but was killed in the following Battle of St. Matthew's Day in September 1217.

This position aligns with the responsibilities typically associated with a king or a supreme military leader The only written biographical information about Lembit comes from the Livonian Chronicle of Henry, where he is described as "senior" ("elder") and " "princeps ac senior perfidus Lembitus" ("perfidious prince and elder Lembitu").