Moving backwards from 1508 to 1503 one comes across two specific periods during which Leonardo lived in Florence: one lasting from August 1507 to the spring of 1508 and a longer stay Ė which began with his return from the Romagna expedition and continued (interrupted perhaps by a brief stay in Rome before 27 April 1504 until June 1506. It is to this period that the historic outline for the painting of the Battle of Anghiari, on sheet 74 r. -b and v. -c of the Atlantico Codex must refer, written (as shown by a note by Solmi by NicolÚ Machiavelli, around the time that the painting is dated and that is, probably, in October 1503 But, contrarily to what Solmi supposes, this sheet is independent of the pages (Atlantico Codex 74 r.-a, b, v. -b), in which Leonardo drew up a copious list (which is completed on sheet 79 r.-a, b, and 79 v.-b of the same Codex) of the topics in the Treatise on water: a list which proves very interesting to compare with the Leice-