Five weeks earlier, Edward's father had ridden into a Lancastrian trap at Wakefield and been killed. The Duke of York's claim to the English throne, secured by the Act of Accord just months before, now passed to his teenage son. Edward had been gathering support in the Welsh Marches when the news reached him at Gloucester over Christmas. He was preparing to ride for London when scouts brought word that Jasper Tudor and his father Owen were leading a Lancastrian army out of Wales, intending to link up with Queen Margaret of Anjou's main force. If those armies joined, the war was effectively over. Edward turned north from Gloucester with perhaps five thousand men, racing to intercept the Tudors near the crossroads at Mortimer's Cross, in the heart of the family lands he had inherited from his grandmother.

Parhelia, sometimes called sun dogs, occur when sunlight refracts through hexagonal ice crystals high in the atmosphere on bitterly cold mornings. The result is two bright spots flanking the real sun, each appearing as a separate disc in the sky. To 15th-century soldiers waiting in a frozen Herefordshire valley, it was something else entirely. Medieval armies read portents the way modern commanders read weather reports. A triple sun, on the dawn of battle, was either a blessing or a curse, and Edward could feel his men deciding which. He read the moment perfectly. Three suns, he announced, were the three persons of the Trinity itself, set burning over the field as a sign of divine favour. He took the sun in splendour as his personal badge that day, and it would adorn his banners for the rest of his reign. Shakespeare put the moment into Henry VI, Part 3, though oddly he never wrote the battle that followed.

The fighting itself was over by mid-afternoon. Sir Richard Croft of nearby Croft Castle had urged Edward to anchor his line at the meeting of Roman roads, archers positioned to rake the Lancastrian advance. James Butler, Earl of Wiltshire, led the first assault and drove back Edward's right wing with his French, Breton and Irish mercenaries. Jasper Tudor's centre held against Edward's. The battle hinged on Owen Tudor's attempted encirclement of the Yorkist left flank, which collapsed instead into a rout. When his wing broke, the rest of the Lancastrian line followed. Welshmen and mercenaries fled west and south, pursued seventeen miles to Hereford. Owen Tudor himself was captured and beheaded in Hereford's market square, where a half-mad local woman is said to have washed his severed head and combed its bloody hair. He was the grandfather of Henry VII. Some Tudors would never forget the road from Mortimer's Cross.

Two months later Edward was crowned Edward IV in Westminster Abbey, the sun in splendour stitched into his vestments. Jasper Tudor escaped to fight on for another decade and to shepherd his young nephew Henry into eventual exile in Brittany. That nephew would return in 1485 to take the crown at Bosworth, ending the Wars of the Roses on a different Welsh frontier. The battlefield at Mortimer's Cross is quiet farmland now, the exact alignment of the armies still debated by historians. A small memorial column stands near the village of Kingsland, and chronicler William Gregory's phrase echoes through every account: Edward 'met his enemies on a fair plain near to Mortimer's Cross, not far from Hereford East'. From the air, you can trace the bend of the River Lugg and the line of the old Roman road, and imagine three suns burning cold above the frost.