Skanderbeg was sent as a hostage to the Ottoman court in Adrianople (Edirne) in 1415, and again in 1423.
It is assumed that he remained at Murad II's court as iç oğlan for a maximum of three years, where he received military training at Enderun.

The earliest existing record of George's name is the First Act of Hilandar from 1426, when John Castriot and his four sons donated the right to the proceeds from taxes collected from two villages in Macedonia (in modern Mavrovo and Rostuša, North Macedonia) to the Serbian monastery of Hilandar.
Afterwards, between 1426 and 1431, John Castriot and his sons, with the exception of Stanisha, purchased four adelphates (rights to reside on monastic territory and receive subsidies from monastic resources) to the Saint George tower and to some property within the monastery as stated in the Second Act of Hilandar.

After graduating Enderun, the sultan granted Skanderbeg control over one timar (land grant) which was near the territories controlled by his father.
His father was concerned that the sultan might order Skanderbeg to occupy his territory and informed Venice about this in April 1428.
In the same year John had to seek forgiveness from the Venetian Senate because Skanderbeg participated in Ottoman military campaigns against Christians.
In 1430, John was defeated in battle by the Ottoman governor of Skopje, Ishak Bey, and as a result, his territorial possessions were extremely reduced.
Later that year, Skanderbeg continued fighting for Murad II in his expeditions, and gained the title of sipahi.
Several scholars have assumed that Skanderbeg was given a fiefdom in Nikopol in northern Bulgaria, because a certain "Iskander bey" is mentioned in a 1430 document holding fiefs there.
Although Skanderbeg was summoned home by his relatives when Gjergj Arianiti and Andrew Thopia along with other chiefs from the region between Vlorë and Shkodër organized the Albanian revolt of 1432–1436, he did nothing, remaining loyal to the sultan.

In 1437–38, he became a subaşi (governor) of the Krujë subaşilik before Hizir Bey was again appointed to that position in November 1438.
Until May 1438, Skanderbeg controlled a relatively large timar (of the vilayet of Dhimitër Jonima) composed of nine villages which previously belonged to his father (registered as "Giovanni's land", Turkish: Yuvan-ili).
According to İnalcık, at that time Skanderbeg was referred to in Ottoman documents as Juvan oglu Iskender bey.
It was because of Skanderbeg's display of military merit in several Ottoman campaigns, that Murad II (r. 1421–51) had given him the title of vali.
At that time, Skanderbeg was leading a cavalry unit of 5,000 men.

After his brother Reposh's death on 25 July 1431 and the later deaths of Kostandin and Skanderbeg's father (who died in 1437), Skanderbeg and his surviving brother Stanisha maintained the relations that their father had with the Republic of Ragusa and the Republic of Venice; in 1438 and 1439, they sustained their father's privileges with those states.

During the 1438–43 period, he is thought to have been fighting alongside the Ottomans in their European campaigns, mostly against the Christian forces led by Janos Hunyadi.
In 1440 Skanderbeg was appointed sanjakbey of Dibra.

During his stay in Albania as Ottoman governor, he maintained close relations with the population in his father's former properties and also with other Albanian noble families.
Skanderbeg was sent as a hostage to the Ottoman court in Adrianople (Edirne) in 1415, and again in 1423. It is assumed that he remained at Murad II's court as iç oğlan for a maximum of three years, where he received military training at Enderun.
The earliest existing record of George's name is the First Act of Hilandar from 1426, when John Castriot and his four sons donated the right to the proceeds from taxes collected from two villages in Macedonia (in modern Mavrovo and Rostuša, North Macedonia) to the Serbian monastery of Hilandar. Afterwards, between 1426 and 1431, John Castriot and his sons, with the exception of Stanisha, purchased four adelphates (rights to reside on monastic territory and receive subsidies from monastic resources) to the Saint George tower and to some property within the monastery as stated in the Second Act of Hilandar.
After graduating Enderun, the sultan granted Skanderbeg control over one timar (land grant) which was near the territories controlled by his father. His father was concerned that the sultan might order Skanderbeg to occupy his territory and informed Venice about this in April 1428. In the same year John had to seek forgiveness from the Venetian Senate because Skanderbeg participated in Ottoman military campaigns against Christians. In 1430, John was defeated in battle by the Ottoman governor of Skopje, Ishak Bey, and as a result, his territorial possessions were extremely reduced. Later that year, Skanderbeg continued fighting for Murad II in his expeditions, and gained the title of sipahi. Several scholars have assumed that Skanderbeg was given a fiefdom in Nikopol in northern Bulgaria, because a certain "Iskander bey" is mentioned in a 1430 document holding fiefs there. Although Skanderbeg was summoned home by his relatives when Gjergj Arianiti and Andrew Thopia along with other chiefs from the region between Vlorë and Shkodër organized the Albanian revolt of 1432–1436, he did nothing, remaining loyal to the sultan.
In 1437–38, he became a subaşi (governor) of the Krujë subaşilik before Hizir Bey was again appointed to that position in November 1438. Until May 1438, Skanderbeg controlled a relatively large timar (of the vilayet of Dhimitër Jonima) composed of nine villages which previously belonged to his father (registered as "Giovanni's land", Turkish: Yuvan-ili). According to İnalcık, at that time Skanderbeg was referred to in Ottoman documents as Juvan oglu Iskender bey. It was because of Skanderbeg's display of military merit in several Ottoman campaigns, that Murad II (r. 1421–51) had given him the title of vali. At that time, Skanderbeg was leading a cavalry unit of 5,000 men.
After his brother Reposh's death on 25 July 1431 and the later deaths of Kostandin and Skanderbeg's father (who died in 1437), Skanderbeg and his surviving brother Stanisha maintained the relations that their father had with the Republic of Ragusa and the Republic of Venice; in 1438 and 1439, they sustained their father's privileges with those states.
During the 1438–43 period, he is thought to have been fighting alongside the Ottomans in their European campaigns, mostly against the Christian forces led by Janos Hunyadi. In 1440 Skanderbeg was appointed sanjakbey of Dibra.
During his stay in Albania as Ottoman governor, he maintained close relations with the population in his father's former properties and also with other Albanian noble families.
Skanderbeg