The Ambitious Collapse of Juan I of Castile

The late 14th century witnessed the dramatic unraveling of Castilian King Juan I’s ambitions, marking a pivotal moment in Iberian and European politics. His ill-fated campaign in Portugal, culminating in the disastrous Battle of Aljubarrota (1385), shattered Castile’s hard-won regional dominance over the preceding decades. As news of the defeat reached England, John of Gaunt—claimant to the Castilian throne through his marriage to Constance of Castile—saw an opportunity. Despite looming French invasion threats, Gaunt secured funds from his nephew, King Richard II, and sailed to Iberia in July 1386 with 2,000 cavalry and 2,000 longbowmen. This expedition, however, would unfold against a backdrop of political turmoil in England, where noble factions clashed over war financing and royal authority.

England’s Domestic Crisis: The “Merciless Parliament”

While Gaunt pursued his Iberian ambitions, England teetered on the brink of civil strife. Richard II’s reliance on controversial advisors like Michael de la Pole, Earl of Suffolk, fueled aristocratic resentment. By 1386, the “Wonderful Parliament” (later dubbed the “Merciless Parliament”) had seized control, impeaching Suffolk and installing a regency council dominated by hostile magnates: Thomas of Woodstock (Duke of Gloucester), Richard FitzAlan (Earl of Arundel), and Thomas de Beauchamp (Earl of Warwick). These “Lords Appellant” accused the king’s circle of corruption and mismanagement, exploiting wartime financial strain to justify their power grab.

The crisis escalated in December 1387 when royalist forces under Robert de Vere were crushed at Radcot Bridge. Richard II, effectively imprisoned, watched as his supporters were purged in the 1388 “Merciless Parliament”—a watershed moment that established Parliament’s right to try royal ministers.

France’s Foiled Invasion and Breton Intrigues

Across the Channel, France’s planned invasion of England repeatedly faltered. In 1386, autumn storms dispersed a massive Franco-Castilian fleet, while political infighting sabotaged a 1387 campaign. The arrest of Constable Olivier de Clisson by John V, Duke of Brittany—a feud rooted in territorial rivalries—further destabilized French efforts. Brittany’s subsequent appeal to England for aid reignited cross-Channel hostilities, but French internal divisions proved insurmountable.

Military Campaigns and Strategic Stalemates

England’s military ventures yielded mixed results. In 1387, Arundel’s naval raids on Sluys and Brest brought plunder but no lasting gains. Meanwhile, Gaunt’s Iberian campaign fizzled; his 1387 treaty with Castile secured minor concessions but abandoned his dynastic claims. By 1388, England faced simultaneous threats: Scottish invasions (notably the Battle of Otterburn, where Henry “Hotspur” Percy was captured) and French coastal raids. The Lords Appellant’s war policy strained resources without altering the continental balance.

Legacy: A Prelude to Greater Conflicts

These events foreshadowed future upheavals. Richard II’s resentment of the Appellants would fuel his later absolutism and eventual deposition. Gaunt’s daughter Philippa’s marriage to Portugal’s João I cemented the Anglo-Portuguese Alliance, enduring to this day. Meanwhile, France’s internal fractures presaged the Armagnac-Burgundian strife that would weaken it during the Hundred Years’ War. The era’s political and military tumult underscored the fragility of medieval state-building, where personal ambitions and institutional rivalries could undo decades of consolidation.

The 1380s thus stand as a microcosm of late medieval power dynamics—where crowns rose and fell on the tides of aristocratic loyalty, financial endurance, and sheer luck.