Louis of Hungary invades the territories held by the Lithuanian prince George in Lodomeria in summer 1377.

His Polish troops soon capture Chelm, while Louis seizes George's seat, Belz, after besieging it for seven weeks.

He incorporates the occupied territories in Lodomeria, together with Galicia, into the Kingdom of Hungary.

Three Lithuanian princes—Fedor, Prince of Ratno, and two princes of Podolia, Alexander and Boris—accept Louis's suzerainty.

The earliest settlements in the area of present day Vilnius appear to be of Mesolithic origin.

Numerous archaeological findings in different parts of the city prove that the area has been inhabited by peoples of various cultures since the early Middle Ages.

Initially a Baltic settlement, later it will also be inhabited by Slavs, Jews and Germans.

Some historians identify the city with Voruta, a forgotten capital of King Mindaugas.

The city, first mentioned in written sources in 1323, is also mentioned as the capital city of Lithuania in the same year by Gediminas, Grand Duke of Lithuania, who built his wooden castle on the hill there.

The city had become more widely known after he wrote a circular letter of invitation to Germans and Jews (known as the Letters of Gediminas) to the principal Hansa towns in 1325, offering free access into his domains to men of every order and profession.

Emperor Louis IV in 1337 had allegedly granted the Teutonic Order the imperial privilege to conquer all Lithuania and Russia, and during the reign of Grand Master Winrich von Kniprode (1351-1382), the Order reaches the peak of its international prestige, hosting numerous European crusaders and nobility.

The Teutonic Knights in 1377 destroy Vilnius.

The Lackfis' influence in Hungary has diminished and new favorites have emerged in the royal court.

James Szepesi had been appointed judge royal in 1373, and Nicholas Garay had become the palatine in 1375.

The organization of central government has also been modified to create a more centralized power structure.

Louis's "secret seal", that he has always taken with him during his wars and journeys, has been declared authentic, and Louis has entrusted it to the secret chancellor who is always to accompany him.

A new high official, the Lord Chancellor is authorized to use the great seal in the king's name in 1376 or 1377.

Demetrius, Bishop of Zagreb, who is of humble origin, is the first to hold this new office.

The Lord Chancellor becomes the head of a new central court of justice, called the court of "the king's special presence" in 1377.

From around the same time, the royal free towns delegate jurors to assist the master of the treasury, who heads the court of appeal for the towns.

A new official, the treasurer, takes over the master of the treasury's financial duties.

Andronikos has made the mistake of favoring the Genoese too highly by awarding it Tenedos.

The governor there refuses to hand it over, and passes it on to Venice.

In the same year, 1377, he crowns his young son John VII as co-emperor on October 18, 1377.

Bukka I, co-founder and second ruler of the kingdom of Vijayanagar, dies in 1377; his son succeeds him as Harichara II.

Bahmani’s ruler, Muhammad Shah I, dies in 1377.

Under his successor, Bahmani narrowly fails in its attack against the capital city of the Vijayanagar kingdom.

The energetic Stephen Tvrtko, taking advantage of internal crises among traditional Bosnian rivals Serbia and Hungary, has recovered Bosnia's lost territory, extended his lands along the Adriatic coast and into Serbia, and, as the Nemanjic dynasty had expired in 1371, in 1377 crowns himself “king of the Serbs, of Bosnia, and of the coast,” trumpeting his alleged Nemanja heritage; he will eventually add to his title Dalmatia and Croatia as well.

Whether his suzerain, Louis of Hungary, had approved Tvrtko's coronation cannot be decided.

Pope Gregory XI dispatches Cardinal Robert of Geneva (the future Avignon Pope Clement VII) in 1377 at the head of a papal army that ruthlessly ravages the territory of the states in revolt, enabling the pope to return to Italy and establish the Holy See in Rome, de facto ending the Avignon Papacy.

Gregory X arrives in Rome in January 1377, after a difficult journey (including shipwreck).

Aided by the intercession of the religious mystic Catherine of Siena, Gregory secures an armistice with Florence and demands an indemnity of one million florins, but dies in March 1377.

Hawkwood has honored his agreement with the Florentines not to make war in Tuscany, limiting himself to putting down the various rebellions within the papal states; in 1377, Hawkwood abandons Gregory XI entirely and joins the anti-papal coalition.

Gregory XI's other condottieri also limit their activities to Romagna, notably sacking Cesena in February 1377.

Papal mercenaries recapture Bologna in the spring of 1377, which up until this point has been a key Florentine ally.