Morta (died c. 1263) was the Grand Duchess of Lithuania (until 1253) and later Queen of Lithuania (1253–1262). There is very little known about her life; even her pre-Christianised name is unknown (she was baptized c. 1252 by the bishop of Chełmno). The only clue into her origin or birthplace is a short mention in the comments following the treaty signed in 1219 between the Lithuanian dukes and Galicia–Volhynia. It says that Mindaugas killed many members of the Bulaičiai family, including Vismantas whose wife Mindaugas took for himself. It is generally assumed that Morta was Vismantas' wife. Edvardas Gudavičius, a modern Lithuanian historian, based on toponyms, determined that the Bulaičiai family most likely came from the Šiauliai region. Based on this evidence and hypotheses, residents of Šiauliai call the city home of Morta.
It is known that Mindaugas had more than one wife. Probably, Morta was his second wife as Vaišvilkas, eldest son of Mindaugas, was already a mature man active in international politics when Morta's sons were still young and dependent on the parents. After her death, Mindaugas married her sister, the wife of Daumantas. It is also known that two of her sons were killed together with Mindaugas in 1263.
The written sources contain little information on Morta's family and it is not entirely clear how many children she had. The chronicles mention two sons, Replys and Gerstukas, in 1261. In 1263 two sons, Ruklys and Rupeikis, were assassinated together with Mindaugas. This is the only information available and historians disagree on whether these were the same two sons, whose names were distorted by medieval scribes, or whether there were four sons.
- (Lithuanian) Tomas Baranauskas, Karalienė Morta ir Šiauliai (Queen Morta and Šiauliai), Vartiklis.lt. Accessed July 9, 2006.