Brother Cadfael 16: The Heretic's Apprentice

house - perhaps French or German. Have we your leave, daughter, to examine it inside?"
    Fortunata's curiosity was already caught and held. She was leaning forward eagerly to follow whatever Anselm might have to demonstrate. "Yes, open it!" she said, and herself proffered the key.
    Girard turned the key in the lock and raised the lid, to lift out upon Anselm's desk the little leather bags that uttered their brief insect sound as he handled them. The interior of the box was lined with pale brown vellum. Anselm raised it to the light and peered within. One corner of the lining was curled up slightly from the wood, and a thin edge of some darker colour showed there, pressed between vellum and wood. He drew it out carefully with a fingernail, and unrolled a wisp of dark purple membrane, frayed from some larger shape, for one edge of it was fretted away into a worn fringe, where it had parted; the rest presented a clear, cut edge, the segment of a circle or half-circle. So small a wisp, and so inexplicable. He smoothed it out flat upon the desk. Hardly bigger than a thumbnail, but the cut side was a segment of a larger curve. The colour, though rubbed, and perhaps paler than it had once been, was nevertheless a rich, soft purple.
    The pale lining in the base of the box seemed also to have the faintest of darker blooms upon its surface here and there. Cadfael drew a nail gently from end to end of it, and examined the fine dust of vellum he had collected, bluish rose, leaving a thin, clean line where he had scratched the membrane. Anselm stroked along the mark and smoothed down the ruffled pile, but the streak was still clear to be seen. He looked closely at his fingertip, and the faintest trace of colour was there, the translucent blue of mist. And something more, that made him look even more closely, and then take up the box again and hold it full in the sunlight, tilting and turning it to catch the rays. And Cadfael saw what Anselm had seen, trapped in the velvety surface of the leather, invisible except by favour of the light, the scattered sparkle of gold dust.
    Fortunata stood gazing curiously at the wisp of purple smoothed out upon the desk. A breath would have blown it away. "What can this have been? What was it a part of?"
    "It is a fragment from a tongue of leather, the kind that would be stitched to the top and base of the spines of books, if they were to be stored in chests. Stored side by side, spine upward. The tongues were an aid to drawing out a single book."
    "Do you think, then," she pursued, "that there was once a book kept in this box?"
    "It's possible. The box may be a hundred, two hundred years old. It may have been in many places, and used for many things before it found its way into the market in Tripoli."
    "But a book kept in this would have no use for these tongues," she objected alertly, her interest quickening. "It would lie flat. And it would lie alone. There is no room for more than one."
    "True. But books, like boxes, may travel many miles and be carried in many ways before they match and are put together. By this fragment, surely it did once carry a book, if only for a time. Perhaps the monks who sold the box had kept their breviary in it. The book they would not part with, even when they were destitute. In their monastery it may have been one of many in a chest, and they could not carry all, when the raiders from Mosul drove them out."
    "This leather tongue was well worn," Fortunata continued her pursuit, fingering the frayed edge worn thin as gauze. "The book must have fitted very close within here, to leave this wisp behind."
    "Leather perishes in the end," said Girard. "Much handling can wear it away into dry dust, and the books of the office are constantly in use. If there's such a threat from these Mamluks of Mosul, the poor souls round Edessa would have little chance to copy new service books."
    Cadfael had begun thoughtfully restoring the felt bags of coins to the casket, packing them solidly. Before the base was covered he drew a finger along the vellum again, and studied the tip in the sunlight, and the invisible grains of gold caught the light, became visible for a fleeting instant, and vanished again as he flexed his hand. Girard closed the lid and turned the key, and picked up the box to tuck it under his arm. Cadfael had rolled up the bags tightly to muffle all movement, but even so, when the box was tilted, he caught the very faint and brief chink as silver pennies