Richard of Bordeaux and Henry Bolingbroke were first cousins, born just three months apart. Their lives were entwined from the beginning. When they were still children, Richard was crowned King Richard II with Henry at his side, carrying the sword of state: a ten-year-old lord in the service of his ten-year-old king.

Yet, as the animals on their heraldic badges showed, they grew up to be opposites: Richard was the white hart, a thin-skinned narcissist, and Henry the eagle, a chivalric hero, a leader who inspired loyalty where Richard inspired only fear. Henry had all the qualities Richard lacked, all the qualities a sovereign needed, bar one: birth right. Increasingly threatened by his charismatic cousin, Richard became consumed by the need for total power, in a time of constant conflict, rebellions and reprisals. When he banished Henry, the stage was set for a final confrontation, as the hart became the tyrant and the eagle his usurper.

Theirs is a story of power, legitimacy, and the limits of rule and resistance. In her 2025 Lancaster History Lecture, Helen Castor shows how, in Richard’s hands, kingship became tyranny, and explores the costs – personal, political and constitutional – of opposing the threat he came to represent.

Helen Castor is an acclaimed medieval and Tudor historian whose books include the prize-winning Blood & Roses and She-Wolves: The Women Who Ruled England before Elizabeth. She has presented a range of radio and television programmes for the BBC and Channel 4. She is a Fellow of the Royal Society of Literature and a Fellow Commoner of Sidney Sussex College, Cambridge, and was a judge for the 2022 Booker Prize. She lives in London.

Dr Sophie Thérèse Ambler is Reader in Medieval History, Director of the Centre for War and Diplomacy and a Research Fellow at The Ruskin at Lancaster University. She is the author of The Song of Simon de Montfort.