Fell to his two uncles, John of Bedford and Humphrey of Gloucester, the two surviving brothers of the late king.
An attempt made by his uncles to dislodge him proved unsuccessful, and no sooner was the young sovereign firmly settled than he began to meditate an extension of his own dominions.
He surrendered himself to the British in November; in April 1889 he and two of his uncles (under whose influence he chiefly acted) were found guilty of high treason and were exiled to St Helena.
John at first sought to conceal his share in the murder, but ultimately decided to confess to his uncles, and abruptly left Paris.
When his father died in 1381 some trouble arose over the family possessions, and in the following year an arrangement was made by which Frederick and his brothers shared Meissen and Thuringia with their uncles Balthasar and William.