This is more or less what happened in Korea 1398. The new Joseon dynasty was only six years old, having replaced the old Goreyo dynasty relatively bloodlessly, and conflict was rife.

Yi Seonggye, the founding monarch of the Joseon dynasty, had eight sons, the first six by his first wife and the last two by his second wife. The issue was that the king adored his young second wife and his children with her, to the point that Yi Seonggye finally took the extreme step of making his youngest son the heir to the throne despite his seven older brothers (East Asian dynasties normally practiced primogeniture).

Yi Bangwon, the ambitious fifth son of Yi Seonggye, was understandably angry, as he had been a key figure in making the founding of the Joseon possible and yet was not included in the list of meritorious retainers nor made heir. Finally, Yi Seonggye and Jeong Dojeon, the king's trusted adviser, began to take steps to dissolve the private armies that menaced the stability of central authority. But for Yi Bangwon and others like him, it was like a death knell, because the dissolution and absorption of private armies meant that they would have no military force to defend themselves against the state.

In August 26, Yi Bangwon and his associates and some of his brothers (including older ones) led a coup against the king under the pretense that Jeong Dojeon, etc, was plotting to massacre the princes. A small army was gathered and armed by Yi Bangwon's wife. After holding a demonstration before the palace gate, the rebels attacked a house where Jeong Dojeon was drinking with acquaintances and set it on fire. Jeong Dojeon fled but was soon killed, as were two of his sons (another son committed suicide). The palace guard was disarmed by a commander who was in leagues with the prince, and another commander was killed. The coup was over.

After the coup, the second son of Yi Seonggye was made heir to give the rebellion a veneer of legitimacy (the oldest son was already dead). The two sons of Yi Seonggye's second queen were discretely murdered; the old king himself soon abdicated. Two years later, Yi Bangwon finally took the throne after yet another abdication.

Yi Seonggye died ten years after his two sons and a trusted adviser were murdered by his own son; he retired to his old hometown in the northeast where he had grown up before entering the court, and his belief in Buddhism grew ever deeper. Today, the king's grave is wreathed in grass from his hometown.

Just Europe, or are other places okay too?