Manuel II Palaiologos was the second son of Emperor John V Palaiologos and his wife Helena Kantakouzene.

Granted the title of despotēs by his father, the future Manuel II traveled west to seek support for the Byzantine Empire in 1365 and in 1370, serving as governor in Thessalonica from 1369.
The failed attempt at usurpation by his older brother Andronikos IV Palaiologos in 1373 led to Manuel's being proclaimed heir and co-emperor of his father.
 In 1376–1379 and again in 1390 they were supplanted by Andronikos IV and then his son John VII, but Manuel personally defeated his nephew with help from the Republic of Venice in 1390.
Although John V had been restored, Manuel was forced to go as an honorary hostage to the court of the Ottoman Sultan Bayezid I at Prousa (Bursa).
During his stay, Manuel was forced to participate in the Ottoman campaign that reduced Philadelpheia, the last Byzantine enclave in Anatolia.

Having heard of his father's death in February 1391, Manuel II Palaiologos fled the Ottoman court and secured the capital against any potential claim by his nephew John VII.
 Although relations with John VII improved, Sultan Bayezid I besieged Constantinople from 1394 to 1402.
 After some five years of siege, Manuel II entrusted the city to his nephew and embarked (along with a suite of 40 people) on a long trip abroad to seek assistance against the Ottoman Empire from the courts of western Europe, including those of Henry IV of England (making him the only Byzantine emperor ever to visit England – he was welcomed from December 1400 to January 1401 at Eltham Palace, and a joust took place in his honour), Charles VI of France, Sigismund the Holy Roman Emperor, Queen Margaret I of Denmark and king Martin of Aragon.
In 1399, the French King Charles VI sent Marshal Jean Le Maingre with six ships carrying 1,200 men from Aigues-Mortes to Constantinople; later 300 men under Seigneur Jean de Chateaumorand remained to defend the city against Bayezid.

Meanwhile, an anti-Ottoman crusade led by the Hungarian King Sigismund of Luxemburg failed at the Battle of Nicopolis on 25 September 1396, but the Ottomans were themselves crushingly defeated by Timur at the Battle of Ankara in 1402.
Manuel II had sent 10 ships to help in the Crusade of Nicopolis.
As the sons of Bayezid I struggled with each other over the succession in the Ottoman Interregnum, John VII was able to secure the return of the European coast of the Sea of Marmara and of Thessalonica to the Byzantine Empire in the Treaty of Gallipoli.
When Manuel II returned home in 1403, his nephew duly surrendered control of Constantinople and received as a reward the governorship of newly recovered Thessalonica.
The treaty also regained from the Ottomans Nesebar (1403–1453), Varna (1403–1415), and the Marmara coast from Scutari to Nicomedia (between 1403–1421).

On 25 July 1414, with a fleet consisting of four galleys and two other vessels carrying contingents of infantry and cavalry, departed Constantinople for Thessalonica.
The purpose of this force soon became clear when he made an unannounced stop at Thasos, a normally unimportant island which was then under threat from a son of the lord of Lesbos, Francesco Gattilusio.
It took Manuel three months to reassert imperial authority on the island.
Only then did he continue on to Thessalonica, where he was warmly met by his son Andronicus, who then governed the city.

In the spring of 1415, he and his soldiers left for the Peloponnese, arriving at the little port of Kenchreai on Good Friday, 29 March.
Manuel II Palaiologos used his time there to bolster the defences of the Despotate of Morea, where the Byzantine Empire was actually expanding at the expense of the remnants of the Latin Empire.
 Here Manuel supervised the building of the Hexamilion (six-mile wall) across the Isthmus of Corinth, intended to defend the Peloponnese from the Ottomans.

Manuel II stood on friendly terms with the victor in the Ottoman civil war, Mehmed I (1402–1421), but his attempts to meddle in the next contested succession led to a new assault on Constan
Manuel II Palaiologos was the second son of Emperor John V Palaiologos and his wife Helena Kantakouzene. 
Granted the title of despotēs by his father, the future Manuel II traveled west to seek support for the Byzantine Empire in 1365 and in 1370, serving as governor in Thessalonica from 1369. The failed attempt at usurpation by his older brother Andronikos IV Palaiologos in 1373 led to Manuel's being proclaimed heir and co-emperor of his father.  In 1376–1379 and again in 1390 they were supplanted by Andronikos IV and then his son John VII, but Manuel personally defeated his nephew with help from the Republic of Venice in 1390. Although John V had been restored, Manuel was forced to go as an honorary hostage to the court of the Ottoman Sultan Bayezid I at Prousa (Bursa). During his stay, Manuel was forced to participate in the Ottoman campaign that reduced Philadelpheia, the last Byzantine enclave in Anatolia.
Having heard of his father's death in February 1391, Manuel II Palaiologos fled the Ottoman court and secured the capital against any potential claim by his nephew John VII.  Although relations with John VII improved, Sultan Bayezid I besieged Constantinople from 1394 to 1402.  After some five years of siege, Manuel II entrusted the city to his nephew and embarked (along with a suite of 40 people) on a long trip abroad to seek assistance against the Ottoman Empire from the courts of western Europe, including those of Henry IV of England (making him the only Byzantine emperor ever to visit England – he was welcomed from December 1400 to January 1401 at Eltham Palace, and a joust took place in his honour), Charles VI of France, Sigismund the Holy Roman Emperor, Queen Margaret I of Denmark and king Martin of Aragon. In 1399, the French King Charles VI sent Marshal Jean Le Maingre with six ships carrying 1,200 men from Aigues-Mortes to Constantinople; later 300 men under Seigneur Jean de Chateaumorand remained to defend the city against Bayezid.
Meanwhile, an anti-Ottoman crusade led by the Hungarian King Sigismund of Luxemburg failed at the Battle of Nicopolis on 25 September 1396, but the Ottomans were themselves crushingly defeated by Timur at the Battle of Ankara in 1402. Manuel II had sent 10 ships to help in the Crusade of Nicopolis. As the sons of Bayezid I struggled with each other over the succession in the Ottoman Interregnum, John VII was able to secure the return of the European coast of the Sea of Marmara and of Thessalonica to the Byzantine Empire in the Treaty of Gallipoli. When Manuel II returned home in 1403, his nephew duly surrendered control of Constantinople and received as a reward the governorship of newly recovered Thessalonica. The treaty also regained from the Ottomans Nesebar (1403–1453), Varna (1403–1415), and the Marmara coast from Scutari to Nicomedia (between 1403–1421).
On 25 July 1414, with a fleet consisting of four galleys and two other vessels carrying contingents of infantry and cavalry, departed Constantinople for Thessalonica. The purpose of this force soon became clear when he made an unannounced stop at Thasos, a normally unimportant island which was then under threat from a son of the lord of Lesbos, Francesco Gattilusio. It took Manuel three months to reassert imperial authority on the island. Only then did he continue on to Thessalonica, where he was warmly met by his son Andronicus, who then governed the city.
In the spring of 1415, he and his soldiers left for the Peloponnese, arriving at the little port of Kenchreai on Good Friday, 29 March. Manuel II Palaiologos used his time there to bolster the defences of the Despotate of Morea, where the Byzantine Empire was actually expanding at the expense of the remnants of the Latin Empire.  Here Manuel supervised the building of the Hexamilion (six-mile wall) across the Isthmus of Corinth, intended to defend the Peloponnese from the Ottomans.
Manuel II stood on friendly terms with the victor in the Ottoman civil war, Mehmed I (1402–1421), but his attempts to meddle in the next contested succession led to a new assault on Constan
Manuel II Palaiologos