Lengvenis was one of the sons of Algirdas

Algirdas

Algirdas was a monarch of medieval Lithuania. Algirdas ruled the Grand Duchy of Lithuania from 1345 to 1377, which chiefly meant monarch of Lithuanians and Ruthenians...

, Grand Duke of Lithuania, and the ruler of Great Novgorod Republic

Novgorod Republic

The Novgorod Republic was a large medieval Russian state which stretched from the Baltic Sea to the Ural Mountains between the 12th and 15th centuries, centred on the city of Novgorod...

 (1389–1392, 1406–1411). He was known for his skills as a military leader.

Lengvenis was born to Algirdas and his second wife Uliana Alexandrovna of Tver

Uliana Alexandrovna of Tver

Uliana Alexandrovna of Tver was a daughter of Grand Prince Alexander of Tver and Anastasia of Halych, and second wife of Grand Prince of Lithuania Algirdas. After the death of her husband Uliana became a nun under the name Marina...

. In 1387 battle with the Teutonic Knights

Teutonic Knights

The Order of Brothers of the German House of Saint Mary in Jerusalem , commonly the Teutonic Order , is a German medieval military order, in modern times a purely religious Catholic order...

 Lengvenis commanded one of Lithuanian formations. In 1389–1392 he was appointed by his brother Jogaila

Jogaila

Jogaila, later 'He is known under a number of names: ; ; . See also: Jogaila : names and titles. was Grand Duke of Lithuania , king consort of Kingdom of Poland , and sole King of Poland . He ruled in Lithuania from 1377, at first with his uncle Kęstutis...

, Grand Duke of Lithuania and King of Poland, as regent of Great Novgorod. He was baptized in the Orthodox

Eastern Orthodox Church

The Orthodox Church, officially called the Orthodox Catholic Church and commonly referred to as the Eastern Orthodox Church, is the second largest Christian denomination in the world, with an estimated 300 million adherents mainly in the countries of Belarus, Bulgaria, Cyprus, Georgia, Greece,...

 rite as Simon and received the title of Prince of Great Novgorod

Prince of Novgorod

The Prince of Novgorod was the chief executive of Novgorod the Great. The office was originally an appointed one until the late eleventh or early twelfth century, then became something of an elective one until the fourteenth century, after which the Prince of Vladimir was almost invariably the...

. After Lengvenis lost this title in 1392, Vytautas the Great

Vytautas the Great

Vytautas ; styled "the Great" from the 15th century onwards; c. 1350 October 27, 1430) was one of the most famous rulers of medieval Lithuania. Vytautas was the ruler of the Grand Duchy of Lithuania which chiefly encompassed the Lithuanians and Ruthenians...

 appointed him to Mstislavl. In 1406–1411 Lengvenis, once again, was nominated by Vytautas as regent of Great Novgorod. As ruler of Novgorod he led battles against Pskov

Pskov

Pskov is an ancient city and the administrative center of Pskov Oblast, Russia, located in the northwest of Russia about east from the Estonian border, on the Velikaya River. Population: -Early history:...

, Livonian Order

Livonian Order

The Livonian Order was an autonomous Livonian branch of the Teutonic Order and a member of the Livonian Confederation from 1435–1561. After being defeated by Samogitians in the 1236 Battle of Schaulen , the remnants of the Livonian Brothers of the Sword were incorporated into the Teutonic Knights...

, and Sweden

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

.

In 1410, Lengvenis participated in the Battle of Grunwald

Battle of Grunwald

The Battle of Grunwald or 1st Battle of Tannenberg was fought on 15 July 1410, during the Polish–Lithuanian–Teutonic War. The alliance of the Kingdom of Poland and the Grand Duchy of Lithuania, led respectively by King Jogaila and Grand Duke Vytautas , decisively defeated the Teutonic Knights, led...

 and commanded three banners from Smolensk

Smolensk

Smolensk is a city and the administrative center of Smolensk Oblast, Russia, located on the Dnieper River. Situated west-southwest of Moscow, this walled city was destroyed several times throughout its long history since it was on the invasion routes of both Napoleon and Hitler. Today, Smolensk...

. His son Yury commanded one of these banners. In 1411 Lengvenis participated in the signing of the Peace of Thorn. He was married to Maria Dmitrovna, princess of Moscow

Moscow

Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...

, the daughter of Dmitri Donskoi

Dmitri Donskoi

Saint Dmitry Ivanovich Donskoy , or Dmitry of the Don, sometimes referred to as Dmitry I , son of Ivan II the Meek of Moscow , reigned as the Prince of Moscow from 1359 and Grand Prince of Vladimir from 1363 to his death. He was the first prince of Moscow to openly challenge Mongol authority in...

.