The death of King Augustus III in 1763 did not change Radziwiłł's obscure behaviour and addiction to alcohol, which now negatively influenced his highly successful policies and political campaigns.
Furthermore, ambassador Kayserling demanded his separation from Hetman Branicki.
Unlike Czartoryski, who constantly improved and participated in local councils, Radziwiłł neglected his duties, and, on the advice of one of his companions, he concluded several treaties with his closest allies, which eventually resulted in the weakening of his political party and proved to be a harm for the peasants supporting the policies issued by the Lithuanian councils under Radziwiłł's control.
As a result, the election of deputies and court marshals were mostly influenced by the Czartoryskis.
Radziwiłł, trying to repair his delicate and temporary reputation, travelled to Vilnius and in 1764 he established a new, illegal council and proclaimed himself marshal.
The council was mostly focused on diminishing the power of Polish nobility, supportive of the Russian control over the Commonwealth, that resided in the Grand Duchy.
The following day, drunk Radziwiłł broke into the home of Countess Anna Tyszkiewicz, and then to the palace of Bishop Ignacy Massalski where he insulted the royal court and humorously threatened to burn the property.
The sober prince later apologized to the bishop.
Having given up the duties of marshal, in March Karol Stanisław Radziwiłł left Vilnius.
He later sent his militia (approx.
300 men) to defend the Polish diplomatic position at the Prussian council in Grudziądz.

On April 8, 1764 Radziwiłł married Teresa Karolina Rzewuska, the daughter of Hetman Wacław Rzewuski.
The death of King Augustus III in 1763 did not change Radziwiłł's obscure behaviour and addiction to alcohol, which now negatively influenced his highly successful policies and political campaigns. Furthermore, ambassador Kayserling demanded his separation from Hetman Branicki. Unlike Czartoryski, who constantly improved and participated in local councils, Radziwiłł neglected his duties, and, on the advice of one of his companions, he concluded several treaties with his closest allies, which eventually resulted in the weakening of his political party and proved to be a harm for the peasants supporting the policies issued by the Lithuanian councils under Radziwiłł's control. As a result, the election of deputies and court marshals were mostly influenced by the Czartoryskis. Radziwiłł, trying to repair his delicate and temporary reputation, travelled to Vilnius and in 1764 he established a new, illegal council and proclaimed himself marshal. The council was mostly focused on diminishing the power of Polish nobility, supportive of the Russian control over the Commonwealth, that resided in the Grand Duchy. The following day, drunk Radziwiłł broke into the home of Countess Anna Tyszkiewicz, and then to the palace of Bishop Ignacy Massalski where he insulted the royal court and humorously threatened to burn the property. The sober prince later apologized to the bishop. Having given up the duties of marshal, in March Karol Stanisław Radziwiłł left Vilnius. He later sent his militia (approx. 300 men) to defend the Polish diplomatic position at the Prussian council in Grudziądz.
On April 8, 1764 Radziwiłł married Teresa Karolina Rzewuska, the daughter of Hetman Wacław Rzewuski.
Karol Stanisław Radziwiłł (1734–1790)