"Hell awaits betrayers," Marcus hissed. "Especially those who blame great men for their own failures. Londinium was destroyed because you held the Fifteenth back. You were a coward!"

"I held back the Fifteenth because I was ordered to. Ordered by Maxentius."

Quintillius leaned back, his distant eyes looking at no one. "But you are correct in one aspect, Marcus. I was a coward. I knew that lacking the Fifteenth, Londinium would fall. A braver man would have ignored those orders—perhaps pretended he never received them—and marched anyway. A braver man would have fought for his own honor after Maxentius blamed him for the carnage. No, Marcus, I was not a brave man. But I am no deceiver.

"The Northmen honored their agreement—and more. They created the prisoner exchange, not us. After withdrawing north they freed our captured soldiers and the civilians they kept as slaves. At once they offered Rome trade. They even offered to cede Icelandia, at the time home for only a handful of Swedes, to the Empire. . . . "

Marcus heard a little more: that the Icelandia colonists were those Maxentius wanted to be rid of—as Marcus guessed years ago. That the besmirched Quintillius learned of the western continent from Hrolf Hranisson, son of the man who discovered it. Shortly after landfall Quintillius forged—through means he didn't elucidate—a three-way peace between the Northmen, the struggling Romans, and the Skraelings. The colonists decided to keep this land for themselves; the reverie in Quintillius' tone spoke of Paradise itself.

By treaty, Terra Ambrosia was below a river just north of Concordia called the Patomac, the Northmen's provinces above. An outsider attack on Ambrosians or Northmen or Skraelings was considered an attack on all.

The original Concordia was burned so future Roman visitors would think them dead. Another phoenix rose from long-cold ashes alongside the Senate—the People's Assembly, an elected body originally destroyed by the dictator Sulla during the final years of the Republic. Turning captured prisoners into slaves was forbidden since, early on, one solid attack against Castra Concordia could have meant extinction—thus was the prisoner exchange reborn in this new land. Quintillius' details were vague, but ultimately that meant the end of slavery entirely.

Marcus caught nothing else. He was aware of growing uncharacteristically and dangerously unfocused but let his thoughts drift in a fog of anger, confusion, and disbelief. He would not—could not—make himself believe that Maxentius Caesar was the traitor while Quintillius, usurper in a foreign land, was some kind of saving hero. And yet . . . and yet . . .

Maxentius has done many things to . . . preserve himself. Had friends and enemies alike killed, purged the Senate, fled Rome during times of trouble. But would he have sacrificed Londinium?

An angry, nebulous answer seeped into his thoughts until Marcus became aware of everyone rising to their host's words, " . . . Join us?"

Acutely aware of Three Rivers walking airily at his side, Marcus followed Quintillius through the garden—lit by warm moonlight and still intoxicatingly pungent even at this late hour—and to wonders Marcus could hardly have imagined before leaving Rome.

However much his attention drifted before, it stood as rigidly alert as a picket soldier inspected by Caesar himself.

"But how can you make it work?" he demanded. "Must you load powder into each chamber? And why four barrels?"

Nikolaos Azanties shrugged. "Four winds, four corners of the Earth . . . four barrels."

Quintillius handed the weapon to the old Greek's unspeaking but surly-looking apprentice, who broke it with a quick snap. No, it wasn't broken—the boy loaded the weapon where the barrel met the stock, then snapped it shut and passed it off to Nikolaos.

The Greek leaned on the projectius. "We no longer use iron balls. I developed a process to pack powder into individual casings. One chamber, one casing." He lifted the projectius slowly—its relatively light weight was cumbersome for the eighty-year-old. He pulled back the oversized hammer at the stock, shot an unfortunate pine tree, twisted a latch on the weapon's side, fired again. He continued until the projectius was expended.

Marcus' mask was never in danger of failing when he fought the Northmen, or when he leveled Vetera and Aelia Capitolina and ordered the deaths of their stubborn occupiers. Now . . . Four shots in half a minute. One minute to load a normal Roman projectius. If the Northmen ever possessed these weapons . . .

He glanced at Hallbjorn, his stomach knotting. What if the Northmen owned them already? Hallbjorn caught his glance and grinned, mimicking pointing the weapon at the Roman.

" . . . Problem with overheating," the Greek inventor was saying, "so we must be careful not to fire too rapidly. We've also developed the Minutus—a smaller version you may hold in one hand. But come, you must watch Aphrodite and Artemis before their experiments tomorrow."

The old man cheerfully ambled down a gently sloping hillside that sank into a wide, lazy river. Exhaustion still dogged Marcus and his wounds burned; even listening was an effort.

Two bizarre buildings—temples—rose from the shore. They boasted no architectural proportions Marcus could discern. Just two whitewashed iron buildings, long and narrow much like the Dragon ships with an oversized smoke-belching hole in the ceilings. The sides of each boasted a millwheel. On each temple was painted APHRODITE and ARTEMIS respectively.

Temples to pagan gods, Marcus fumed. Bargains with the Adversary. So that is how Quintillius and his little empire have survived so long.

"You have Hero of Alexandria to thank for these as well," Azanties beamed, still clutching the empty multishot projectius like a cane. "When the Basileus Herakleios V allowed me to carry my library into exile he had barely heard of Archimedes, much less Hero. With my gratitude for our ancient friend you have your water pumps, your air circulation pumps, and now—" he swept his hand toward the temples, "—Aphrodite and Artemis."

Only then did Marcus notice the temples were floating. A single man waved from each uppermost room; Nikolaos saluted; men scrambled around the patio casting off ropes and withdrawing planks. A great screech from Aphrodite made Marcus clap his ears—and the temples moved.

The old Greek chortled and rubbed his hands briskly. "Apologies, General Trogia. That magnificent whistle was my fancy."

The millwheels churned and the—ships, it dawned on Marcus with no small horror—swung into the river and sailed against the current.

"All steam powered," Azanties explained. "Tomorrow we test them bearing the loads of a full compliment of cannons. But I have calculated the mathematics one-hundred times and more: The ships will float, and still be as fast as they are now."

Fast indeed. They were already disappearing around a riverbend.