By night the comet was a smear of light against the heavens: a brilliant point with a halo of angel hair trailing behind it. By day it was harder to see; but, if you knew where to look and the sun was in the right quarter, it could still be made out against a clear sky.

Father Ambrosius had been the first to see the comet. It was after evensong, and he was leaving the chapel for his cell to get some rest before the nighttime vigils. He had paused to admire God's firmament where, amongst the familiar constellations, he saw the comet's tail. At first the priest had thought it to be some trick brought about by his failing eyesight. But the comet had remained fixed in the sky no matter which way Father Ambrosius turned his head or how hard he squinted. He watched the new star for a while, fascinated by what he saw, then went to find Brother Michael - a scholar of heavenly phenomena.

"There is a new star in the sky," Ambrosius announced to the drowsy monk.

Michael groaned and scratched at his tonsured scalp. "Ex Africa semper liquid novi," he replied. "Are you sure?"

"I am. Truly. I did not believe it myself at first, but it is there."

The priest chivvied the monk into the yard of the abbey and pointed up. Brother Michael peered into the night sky, muttered something in his native tongue and crossed himself. "What is it?" Ambrosius asked.

"A portent." The monk glanced worriedly at his companion. "It heralds a time of change and uncertainty."

"Pagan superstition," Ambrosius replied with outward confidence. "But I will forgive you for that."

"Perhaps it is superstition, but there are many learned men who would have disagreed with you, father."

By noon of the next day, the 'hairy star' was the talk of the abbey. Many of the monks discussed its import, with some of the more imaginative and excitable ones claiming that the comet was a sign of the End of Days as described by Saint John of Patmos. Indeed, speculation was so great, so wild amongst the holy men that Father Ambrosius asked Abbot Barnabas to issue a decree against such gossip. However, this only added fuel to the fire. After a week the comet was still there, albeit having moved some degrees across the zodiac, as was the world. And so the monks' interest waned.

Father Ambrosius found Brother Michael in the scriptorium. "As I told you - superstition."

But Brother Michael shook his head and pointed upwards. "Ecce. Sed ad est. We shall see who is right."

A month later, the news arrived that an army of Norsemen had landed in Northumbria and that Harold Godwinson would be riding to meet them.