The magician smiled to himself. Yes, this was exactly what he was looking for, it was perfect. In odd little curio shop tucked in one of the backways through the bazaar, he had found the ledger book belonging to a minor functionary of a Great House. It was a quality book, bound in leather with good vellum pages, filled to the last page with dry accounts of good received, payments made, and bargains dealt. Perfect.
He paid for the book. Paid too much, actually. He had put effort into seeming nonchalant and uncaring, like he was doing the shopgirl a favor by taking it off her hands. But she was a sharp one, and sensed his eagerness, damn her. She drove a hard bargain, though she was obviously a little bewildered by his interest in the book.
But no matter, it was his, now.
He hurried back to his workshop where he opened the book on his table. He picked a page at random, then drew in his magic. Carefully, he took the ink from an entry for the number of pigs purchased by the Great House for the feast of St. Agatha, and rearranged it on the page. He made the words scrawling, in the same hand as the original entry, but without any of the meticulous neatness, like the author wasn't quite in his right mind. He wrote disjointed sentences, proclaiming the arrival of a child, something about a great battle.
Selecting another page at random, he did the same thing to another entry, this time adding some vague phrases about how the child would be known. Another entry, with an implication that the child would overthrow the Emperor, and rule in truth and fairness.
The magician thought for a long moment, then selected one last page, and change an entry to declare that the child would arrive with certain signs that he knew happened with some regularity, but vague enough in description to be unclear – a river overflowing its banks, a great migration of birds, a great flash of light in the sky.
This done, he smiled and sat back, pleased with himself. Now he just needed to plant this book somewhere where it would be found, read, and taken seriously by gullible people. It would keep them going around for years.
He would donate the book as part of a gift to the Historical Society, he decided, with a couple other innocuous others to go with it, tomorrow.