The mouse breastplates were of painted leather, framed and cushioned by wickerwork and bound to them with leather thongs. At first glance, their helmets were of leather also, fur side out-but the close inspection which the tribune's wonder granted him showed that the helms were gigantic nut-shells with the shaggy husks still clinging to them.

Neither army carried edged weapons; and, unless Vibulenus were wrong about the spears of the mice, neither army had any metal even as items of adornment.

The tribune's point of view swooped up to a godlike perspective from which the armies, beginning to flow together, were blurred into two unities: the individual warriors shrank from man-size to mere colors, a green jelly and a brown jelly, sliding toward one another across a pan of neutral gray.

"Gaius Vibulenus Caper," said the voice, "you have received the challenge of Lucius Rectinus Falco. Do you accept?"

"What?" blurted the tribune. Below-directly below, not "down" in sense that one looked down from the bleachers onto a gladiatorial combat-the field rang with the cries of the combatants, individually audible when the voice was not speaking in his ears.

"You must accept or not accept," the voice said tartly. "Do you accept?"

"Yes, damn you, but what-"

And Vibulenus spiraled vertiginously down to the marshy battlefield.

He was no longer watching the battle as he lay on a couch which he felt even if he did not see. The shield on his left side was supported by a strap of woven grass over his right shoulder and across his back. It weighed more than even a full-sized legionary's shield, and the leaf from which it had been formed was cured to the density of half an inch of oxhide. More awkward still was the breastplate, a harder, thinner leaf whose serrations prodded the skin of his belly when he strode forward.

That skin was green, with a dozen subtle shades ranging from almost black to almost yellow. His toes splayed at each step, giving him better support than his mind expected when it confronted soil so marshy that water stood around the stems of the coarse, knee-high grass.

Vibulenus was suddenly certain that he was going to die. It wasn't fear, exactly. The feeling was more akin to knowing that you would hit the ground even as you slid over your horse's shoulder.

"Caper, you little coward!" cried one of the oncoming line of mice. "Come out and take your medicine."

Couples of warriors were fighting at intervals between the waiting lines, though when a frog fell or a mouse there would be a general surge from either side and a struggle over the body. One of the mice, striding on hind legs much longer and more powerful than those of the little crumb-nibbler his head and torso mimicked, was coming straight toward Vibulenus. The voice of his sneering challenge was that of Falco, though it came from a furry throat and past great chisel-edged gnawing teeth.

"I'm here, Falco," Vibulenus shouted back. He charged the spear-brandishing mouse, trying to adapt his mind to the unfamiliar-multi-jointed-leg motion his new body found congenial.

Vibulenus held his spear overhand, a little before the balance, so that the butt joggled against his shoulder as he ran. The weapon was much longer than the javelins with which he had trained. That made it unwieldy; but in mitigation of its size, the spear was surprisingly light-certainly no weightier than the heavy pattern of Roman javelin.

All the items of Vibulenus' panoply felt awkward to him, but the frog body he wore was more skillful with them than the tribune had been in battle with legionary equipment. He was not a warrior, but his present muscles and the instincts which came bundled with them were those of a veteran.

The mouse with the voice of Rectinus Falco sank ankle deep at every step, but his shield and spearpoint had a hard glitter that suddenly frightened Vibulenus. His spear was longer than the mouse's, so he thrust in a panicky attempt more to keep his opponent away rather than to do injury.

The frog spearhead was narrow and slightly twisted because it had been flaked from a seashell. The instant it clicked on the face of Falco's shield, Vibulenus feared the shell would shatter and disarm him. The point broke, all right, but it broke into another wedge-shaped profile which would certainly pierce flesh with an arm's full strength behind it.

The mouse rocked at the blow and stumbled, his narrow feet less suited to the marshy surface. Vibulenus cried out in relief which replaced his foreboding as suddenly as lightning tears the limbs from a tree.

He could not follow up on the thrust because his weapon was too long. As his frog hand tried to shorten its grip, he remembered the similar plight of the spearman who had faced him that morning-and Falco, striking desperately, drove the dense, sharp point of his ceramic spear through Vibulenus' shield and into his thigh.

The wounded tribune screamed. The reasoning part of his mind-which had nothing to do with the struggle- noted that the sound was an unfamiliar croak, though when he cried "Wait, Falco!" an instant later the words were in Latin.

"I told you you'd pay!" the mouse shouted as he jerked his weapon free with a slime of pale blood on its tip. He had been off-balance even before he struck, and the effort of clearing the heavy spear cost him his footing. Falco fell with a splash and the terrified cry, "Father!"-his own or perhaps Jove, father of gods and of men. He probably did not know that he had spoken.

Vibulenus' leg trembled with cold fire, but his enemy was under the point of his spear. He stabbed downward as Falco struggled to rise. The shell point chipped again on the edge of the ceramic shield, crazing the surface, then dug into the mouse's breastplate.

Falco tipped over on his back again. The spearpoint was through the leather, but the wickerwork beneath held it for a moment. Vibulenus strode forward, dropping the handle with which he had maneuvered his strap-slung shield and gripping the spear with both hands.

His wounded leg buckled so that he fell sideways.

For a moment, the mouse was still pinned by the spear caught in his breastplate. He slid on his back, twisting, and the point sprang free.

Vibulenus tried to push himself upright with his left hand, but his shield was in the way. His frog body strained upward with terrified bellows, and the strap across his back tugged him down again with identical force.

Falco squirmed into a kneeling position. He had lost his ceramic buckler and held his spear with both hands as he poised with foam dribbling out the corners of his mouth. Vibulenus batted sideways with his own spear, but the shaft was light and an inadequate weapon even if swung with greater force than his exhausted muscles could manage.

The mouse struck back too hastily to rise to his feet first. The blow was clumsy and the spearpoint less sharp than the shimmering glaze had made it seem but the combination sufficed to drive the weapon a hand-breadth into Vibulenus' chest.

It didn't hurt although he could feel the point grate through bones. Vibulenus realized this was all a game. Then his frog body toppled flat in sudden weakness and pain blazed through him with the brilliance of the sun coming from behind a cloud.

Vibulenus was still fully conscious, but the only muscles he could move were those which focused his eyes. The world was wrapped in a pulsing white glow through which the mouse warrior withdrew his weapon and struggled to his feet. Falco must be exhausted also. It was not effort, really, not work done that was so draining. Rather, it was the tension of battle, the emotional tautness that kept every muscle keyed against possible use like a top spinning in place.

Until you collapsed, or you died.

"You've bought it now, dog-spittle!" the mouse wheezed through slobbering jaws, and he drove his spear down at Vibulenus' right eye. The pain stopped, and the universe snuffed all its lights.