In 1503, as he prepared for the Battle of Anghiari mural commissioned for Florence’s Palazzo Vecchio, da Vinci delved into anatomical research aimed at understanding the human body in motion. Although not direct studies for the mural itself, these investigations laid the groundwork for his approach to depicting physical movement. He produced a number of drawings of nude male figures in varied stances and angles. One such study shows a man standing upright with his legs apart for stability, his muscles at rest. This focus on a relaxed state complements other sketches where the musculature is under strain. The drawing reveals remarkable anatomical precision, likely informed by careful observation and perhaps even dissection. Despite the absence of heavy shading, each muscle group—from the back to the calves—is distinctly articulated. The sketch pays particular attention to the figure’s physical subtleties: the play of surface forms, the fluid lines of the body, and the foreshortened hands, all captured through swift, delicate chalk marks. These repeated strokes imbue the figure with a sense of vitality, lifting it beyond mere illustration. Intriguingly, an inscription identifies the model as a musician named Francesco Sinistre, though the reliability of this note is uncertain. It stands out among da Vinci’s human studies, as he typically only annotated such information when drawing horses, including their breed and ownership.