The first Leonardian drawing of a "water stairway" dates to April 1494 (Paris Manuscript H, f. 65 v) and represents the stepped structure still visible in the gardens of the Villa Sforzesca at Vigevano, for regulating waters for purposes of irrigation and reclamation. More than ten years later, in the Codex Leicester, Leonardo mentioned that same artifact several times, and specifically, in relation to the way of constructing weirs that could, through the expedient of "steps", overcome the drawback of erosion along the bottom of the watercourse, downstream from the barrier: “Moreover, if the lowest part of a weir which lies diagonally across the course of the waters be constructed in deep broad steps after the manner of the staircase, the waters which, as they descend in their course, are accustomed to fall perpendicularly from the beginning of this lowest stage, and dig out the foundations of the bank, will not be able any longer to descend with a blow of much impetus; and I give as an example of this the stair down which the water falls from the meadows of the Sforzesca at Vigevano...” (Codex Leicester, f. 21 r; Pedretti ed.) Yet another folio from the same codex proposes a different drawing of the staircase observed at Vigevano, emphasizing primarily the ability this constructional solution had for deriving a watercourse with locks in masonry, without having the drawback of erosion caused by the water at its point of fall (“Stairs of Vigevano, […] down which the water falls without wearing away anything as it finishes its fall. (Codex Leicester, f. 32 r.; Pedretti ed.)) Lastly, again from the Codex Leicester, on folio 22 r, alongside the long digression on the motion of river waters, a drawing depicts Leonardo’s recommendation for the best way to construct the steps in a water stairway: “Thus rivers should not have places from which water falls, unless they are in the form of staircase steps, well dovetailed together and chained; and firmly set one on top of the other. […] Where water has greater percussion, there it will damage the object most; and yet the staircase steps turn out to be the perfect solution, as shown in the upper preceding conclusion. (Pedretti ed.) The weir of the Mill of La Doccia di Vinci, with its masonry staircase, indisputably represents a "Leonardian suggestion", immersed, as it is, in among the places that Leonardo truly did frequent, and, as in the case of the mill mechanism for La Doccia, reproduced on paper.