Parashurama, a significant figure in Hindu mythology, is known for his intense anger and martial skills. The specific event that led Parashurama to enter an assembly in anger is most famously detailed in the narratives surrounding the Mahabharata.

According to the epic, the incident occurred when Parashurama entered the court of King Janaka. He entered it in a fit of anger after hearing about Lord Rama's breaking of the mighty bow of Shiva, called the Pinaka. This action was a part of the swayamvara (a marriage event) for Princess Sita, Janaka's daughter. Parashurama's wrath was due to his vow of protecting the honor of the bow connected to his revered deity, Shiva, and seeing it broken was perceived as a challenge to his own prowess and a slight to the divine.

Parashurama's entry into the assembly is often depicted as a moment of intense drama and tension, where his anger had to be pacified by the wisdom and mediation of other legendary figures, including Lord Rama himself, who managed to appease Parashurama by revealing his true divine identity.

This episode emphasizes themes of duty, respect for elders, and divine intervention, showcasing how Parashurama's initial anger was calmed through dialogue and understanding.

For more detailed accounts, you might refer to comprehensive guides on the Mahabharata or texts discussing Hindu mythology.