In the popular imagination, the Hundred Years’ War is a grand, dynastic struggle between kings: Edward III against Philip VI, the Black Prince against John the Good, Henry V against a broken France. While the crowns of England and France were indeed the ultimate prize, this simplistic narrative obscures a deeper truth. The war was not fought by kings alone. It was a vast, expensive, and brutal enterprise sustained by the immense resources, military acumen, and ambition of England’s great magnate families. And among this warrior aristocracy, none stood higher, wielded more power, or proved more essential to the English war effort than the House of Lancaster.
From its ducal seat in the heart of England, the House of Lancaster projected its influence across the realm and into the battlefields of France. Its story is one of spectacular wealth, political drama, and military prowess, a saga that saw its scions become diplomats, celebrated commanders, and ultimately, usurpers of the very throne they had so powerfully served. For the inhabitants of Lincolnshire, from the fenland manors to the Wold villages like Brattleby, the shadow-sm of the Lancastrian griffon was a constant presence. The duke’s demands for men and money shaped daily life, while his successes and failures in France echoed through the county that formed a cornerstone of his power. This is the story of how the House of Lancaster, forged in the crucible of the Hundred Years’ War, became the indispensable—and most dangerous—subject of the English Crown.
The Foundations of a Super-Duchy
The origins of Lancastrian power lie not in the 14th century, but in the turmoil of the 13th. In 1267, following the baronial rebellion led by Simon de Montfort, King Henry III created the Earldom of Lancaster for his second son, Edmund ‘Crouchback’. This was no mere title; Edmund was endowed with a colossal inheritance, including the confiscated lands of de Montfort and the Earl of Derby. This amalgamation of estates, known as the Honour of Lancaster, was strategically spread across England and Wales, giving the new earldom a national reach unmatched by its peers.
The family’s immense potential for both service and disruption was starkly illustrated by the career of Edmund’s son, Thomas, 2nd Earl of Lancaster. By the reign of his cousin, Edward II, Thomas was unequivocally the richest and most powerful magnate in the kingdom. His annual income, estimated at over £11,000, dwarfed that of any other earl. This vast wealth allowed him to maintain a private army and lead the baronial opposition—the ‘Lords Ordainers’—against the king and his unpopular favourites. Thomas’s challenge to royal authority ultimately ended in disaster. Defeated at the Battle of Boroughbridge in 1322, he was summarily tried and beheaded, his vast estates forfeited to the Crown.
The lesson was clear: Lancastrian power was a double-edged sword. It could prop up the Crown or threaten its very existence. The family’s fortunes were restored by Thomas’s younger brother, Henry, 3rd Earl of Lancaster. A key figure in the deposition of Edward II in 1327, Henry became a loyal guardian to the young Edward III. Though blinded by illness in his later years, he ensured the Lancastrian inheritance was passed on intact, setting the stage for his son, who would raise the family’s prestige to unprecedented heights.
The ‘Good Duke’: Henry of Grosmont, Paragon of Chivalry
The man who truly defined the Lancastrian role in the Hundred Years’ War was Henry of Grosmont, 4th Earl and later the first Duke of Lancaster. A cousin and contemporary of Edward III, Henry embodied the chivalric ideal of his age. He was a founding Knight of the Order of the Garter, a pious Christian who authored a devotional treatise, Le Livre de Seyntz Medicines (“The Book of Holy Doctors”), and, above all, one of the most formidable military commanders of the 14th century. While the Black Prince earned fame for his victories at Crécy and Poitiers, it was Henry of Grosmont who often undertook the gruelling, strategic campaigns that secured English gains.
His masterstroke came in 1345. Dispatched to Gascony as the king’s lieutenant, Henry launched a whirlwind offensive that shattered French control in the region. His campaign began with the storming of the heavily fortified town of Bergerac on the Dordogne, a victory that sent shockwaves through the French command. He followed this with a legendary feat of arms at the Battle of Auberoche. After a ten-day march, Henry’s small Anglo-Gascon force of around 1,200 men a surprise attack on a besieging French army of over 7,000. Under the cover of darkness, they fell upon the French as they were at dinner, creating chaos and routing the much larger force. The chronicler Jean Froissart, ever a connoisseur of martial valour, described the victory as a miracle of generalship. The Auberoche campaign revitalised the English cause in the south-west and secured the resources and loyalty of Gascony for decades to come.
Henry’s service was relentless. He commanded a wing of the English army during the long and arduous Siege of Calais (1346–47). In the 1350s, while the king and prince were occupied elsewhere, he led a series of devastating raids, or chevauchées, deep into French territory, most notably a punishing march through Normandy in 1356 designed to draw the French king, John II, away from the Black Prince’s army. Though he did not arrive in time to participate in the main Battle of Poitiers, his campaign was a crucial part of the strategic picture that led to that epochal English victory.
In recognition of his unparalleled service, wealth, and status, Edward III bestowed upon Henry a unique honour. In March 1351, in full Parliament, he was created Duke of Lancaster. This was the first new ducal title created in England since the Norman Conquest, a sign of quasi-royal status. Crucially, the Duchy of Lancaster was granted palatinate rights—the duke could exercise powers normally reserved for the king within his own territory, such as appointing his own sheriffs and justices and holding his own chancery. He was, in effect, a viceroy in his own domains. This elevation was not merely a reward; it was a strategic move by Edward III to create a powerful, loyal subordinate capable of managing vast resources for the war effort. Henry of Grosmont, the ‘Good Duke’, had made the House of Lancaster a central pillar of the English state at war.
The Lincolnshire Connection: Bolingbroke and the Sinews of War
While Lancastrian power was spread nationally, the county of Lincolnshire was one of its most important heartlands. The inheritance Edmund Crouchback had received included the great Honour of Bolingbroke, which came to the Earls of Lancaster through the de Lacy inheritance. Centred on the formidable Bolingbroke Castle, near Spilsby, this collection of manors, lands, and rights made the Duke of Lancaster the dominant magnate in the county. His estates stretched from the castle itself to coastal manors like Wrangle and Friskney, generating immense revenues from agriculture, rents, and the lucrative wool trade.
This wealth was the financial engine of Lancastrian military power. The profits from Lincolnshire manors directly funded the recruitment of men-at-arms and longbowmen, the purchase of armour and weapons, and the chartering of ships to carry armies to France. The duke’s household at Bolingbroke was a major administrative and military centre. Here, his officials managed the estates, collected revenues, and issued commissions of array to his stewards and local gentry, ordering them to select able-bodied men for military service.
For a small village like Brattleby, located just north of Lincoln, the duke’s influence would have been felt both directly and indirectly. While Brattleby itself was not a direct Lancastrian holding in the mid-14th century—being held for much of the period by families like the Dysnys as part of the larger Honour of Richmond—its inhabitants lived in a shire dominated by Lancastrian interests. The county’s entire economic and social fabric was interwoven with the war. Royal tax commissioners, often acting with the cooperation of the duke’s powerful officials, would have visited local hundreds to assess taxes granted by Parliament to fund the king’s campaigns—the very campaigns led by Henry of Grosmont.
More directly, men from Brattleby and its neighbouring villages would have been subject to the commissions of array. When the Duke of Lancaster needed to raise a retinue, his summons would ripple outwards. Local knights and esquires, perhaps tenants of the duke or simply seeking patronage and the fortunes of war, would muster their own followers. A yeoman from Brattleby, skilled with the longbow, might find himself enlisted not in the king’s army directly, but in the retinue of a local knight sworn to the Duke of Lancaster. He might have marched under the Lancastrian banner in Gascony in 1345 or stood watch on the siege lines at Calais. His wages, his equipment, and his loyalty would be to the Duke, his ultimate commander. In this way, the grand strategy of the Hundred Years’ War was made manifest in the lives of ordinary Lincolnshire people, channelled through the immense gravitational pull of the House of Lancaster.
John of Gaunt: Prince, Magnate, and Kingmaker
In 1361, disaster struck. The Black Death, which had first ravaged England in 1348, returned in a second wave. Among its victims was the ‘Good Duke’ Henry of Grosmont. He left no male heir, only two daughters, Maud and Blanche. For a moment, it seemed the great Lancastrian inheritance might be divided and its unique power diluted. The titles became extinct.
However, Edward III moved swiftly to preserve this vital asset for his family. Maud, who had briefly held the title, died without issue just a year later in 1362. The entire inheritance thus passed to the younger daughter, Blanche of Lancaster. Famously celebrated by Geoffrey Chaucer as the "good, fair White" in The Book of the Duchess, Blanche was already married to the king’s own third surviving son, John of Gaunt. In 1362, Edward III recreated the title of Duke of Lancaster for Gaunt, who now held it jure uxoris (by right of his wife). The super-duchy was reborn, now fused directly with the royal bloodline.
John of Gaunt was to become the defining political figure of the late 14th century. His career was far more complex and controversial than that of his celebrated father-in-law. Where Henry of Grosmont was universally admired, Gaunt was often distrusted as an over-mighty prince with ambitions of his own. His military record in France was mixed at best. His great chevauchée of 1373, a gruelling 900-kilometre march from Calais to Bordeaux, was a logistical marvel but a strategic failure. He lost thousands of men and horses to starvation, disease, and skirmishes, arriving in Gascony with a shattered army and having achieved little of military value.
Gaunt’s focus, however, was not solely on France. Through his second marriage to Constance of Castile, he laid claim to the throne of the Spanish kingdom of Castile and León. This ambition diverted immense Lancastrian and English resources into Iberian campaigns that had little to do with the war against France. For years, he styled himself ‘King of Castile’ and poured his fortune into a fruitless quest for a Spanish crown, a venture that further fuelled suspicion of him back in England.
Despite these foreign entanglements, Gaunt’s power within England was immense. Bolingbroke Castle in Lincolnshire remained a cherished seat; it was here that his son and heir, the future King Henry IV, was born in 1367. As the effective head of government during the minority of his nephew, Richard II, Gaunt was the central figure in English politics. He was a patron of the arts (notably Chaucer) and of the religious reformer John Wycliffe, and his vast wealth and network of retainers made him the ultimate power broker. The Duchy of Lancaster was now more than just a military asset; it was a state within a state, with its own administration, its own foreign policy, and a ruler whose international standing rivalled that of many European monarchs.
From Duke to King: The Lancastrian Usurpation
The very power that had made Lancaster indispensable was now seen as a threat to the Crown. The relationship between John of Gaunt and his nephew, King Richard II, was often tense. Richard, who grew into an autocratic monarch with a high view of his royal prerogative, deeply resented his uncle's influence. Yet, he dared not move against Gaunt directly.
The moment of truth came after Gaunt’s death in February 1399. Gaunt’s son and heir, Henry Bolingbroke (born at Bolingbroke Castle), had been exiled by Richard following a dispute with the Duke of Norfolk. With his powerful uncle now gone, Richard II made a fatal miscalculation. Breaking all precedents of inheritance law and sworn oaths, he declared Bolingbroke a traitor and confiscated the entire Lancastrian inheritance for the Crown.
This act of royal tyranny was a step too far. By dispossessing the greatest nobleman in the land, Richard threatened the property rights of every landowner in England. If the Lancastrian inheritance was not safe, whose was? Henry Bolingbroke, now furnished with a powerful and legitimate grievance, landed at Ravenspur in Yorkshire in July 1399, claiming he had returned only to reclaim his rightful inheritance as Duke of Lancaster.
Nobles, fearing for their own lands, flocked to his banner. The vast network of Lancastrian officials, stewards, and retainers across the country, from Yorkshire to the Midlands and beyond, rose to support their master. The king, who was conveniently absent on campaign in Ireland, returned to find his support had evaporated. Within months, Henry’s quest to recover his duchy transformed into a bid for the Crown itself. Richard II was deposed and, in October 1399, Henry Bolingbroke was acclaimed King Henry IV.
The House of Lancaster had reached its final destination. The power, wealth, and military machine meticulously built up over 130 years, financed by estates like those in Lincolnshire and honed on the battlefields of France, had provided the platform for seizing the throne. The war with France had created the Lancastrian duke; the duke had now become the king.
The story, of course, does not end there. The Lancastrian dynasty would re-ignite the war with spectacular success under Henry V, but their usurpation planted the seeds of future conflict. Their contested claim to the throne would eventually lead to the dynastic civil wars of the 15th century—the Wars of the Roses—where they would face a rival house, York, which also drew its lineage from Edward III. The great paradox of the House of Lancaster is that the very strength which made it such a vital servant of the Plantagenet crown ultimately gave it the power to destroy it and take its place.
Sources & Further Reading
Primary Sources:
Froissart, Jean. Chronicles. Edited and translated by Geoffrey Brereton. Penguin Classics, 1978. (Essential for narrative accounts of the campaigns of Henry of Grosmont and John of Gaunt). Grosmont, Henry of. Le Livre de Seyntz Medicines (The Book of Holy Doctors). Edited by E.J. Arnould. Anglo-Norman Text Society, 1940. (Provides insight into the piety and mindset of the ‘Good Duke’). The Brut or The Chronicles of England. Edited by F.W.D. Brie. Early English Text Society, 1906-8. (A contemporary English perspective on the events). Calendar of the Patent Rolls Preserved in the Public Record Office. H.M. Stationery Office. (Contains official royal grants, including the creation of the Dukedom of Lancaster).
Secondary Sources:
Goodman, Anthony. John of Gaunt: The Exercise of Princely Power in Fourteenth-Century Europe. Longman, 1992. (The definitive biography of Gaunt). Cantor, Norman F. The Last Knight: The Twilight of the Middle Ages and the Birth of the Modern Era. Free Press, 2004. (Contains a highly readable biographical portrait of Henry of Grosmont). Fowler, Kenneth. The King's Lieutenant: Henry of Grosmont, First Duke of Lancaster, 1310-1361. Elek, 1969. (The standard scholarly biography of the ‘Good Duke’). Hill, Sir Francis. Medieval Lincoln. Cambridge University Press, 1948. (Provides detailed local context for Lincolnshire during this period). McFarlane, K.B. The Nobility of Later Medieval England. Oxford University Press, 1973. (A foundational work on the role of the aristocracy in late medieval politics and war). Saul, Nigel. For Honour and Fame: Chivalry in England, 1066-1500. Pimlico, 2011. (Excellent on the cultural context of the warrior aristocracy). Sumption, Jonathan. The Hundred Years War, Vol. I: Trial by Battle and Vol. II: Trial by Fire. Faber & Faber, 1990, 1999. (The most detailed modern history of the war, essential for understanding the campaigns). Walker, Simon. The Lancastrian Affinity, 1361-1399. Clarendon Press, 1990. (A crucial study of how the Lancastrian dukes managed their vast network of retainers and political influence).