Eärnur challenged by the Witch-king
Event Type: Military/Strategic
Age: 3rd Age - The Kings
2043 Eärnur becomes King of Gondor. He is challenged by the the Witch-king.
The Return of the King, LoTR Appendix B, The Tale of Years: The Third Age
When Eärnur received the crown in 2043 the King of Minas Morgul challenged him to single combat, taunting him that he had not dared to stand before him in battle in the North. For that time Mardil the Steward restrained the wrath of the king.
The Return of the King, LoTR Appendix A, Annals of the Kings and Rulers: The Realms in Exile: The Southern Line: Heirs of Anárion
On the death of his father the Lord of the Ringwraiths challenged Earnur to single combat to make good his claim to the throne. Mardil the Steward restrained him.
The Peoples of Middle-Earth, HoME Vol 12, Part 1, Ch 7, The Heirs of Elendil: The Southern Line of Gondor: The Anárioni
[Note: date is nominal to keep events in the right order in the timeline]