This is the Portrait of Girolamo Fracastoro by Titian. Painted in about 1528, it's a portrait of the celebrated medical doctor, as well as an astronomer, mathematician and poet. As you can see, the painting is damaged, but despite that, Titian's touch seems especially apparent in the painting of the lynx fur collar.
The sitter's dynamic pose, turning to look at us over his shoulder with his arm resting on a parapet, reminds me of another portrait by Titian from around 1510. The format of this painting is typical of Titian's early portraiture, with the canvas only slightly taller than it is wide.
Notice how the lynx fur collar is painted in thick broken brushstrokes down the brightly lit left edge, and fine lines scratched into the white paint of the fur tufts trapped in the seams of the sleeve. These details show Titian's technical brilliance as a painter. Despite some loss of modelling on the black parts of the coat, this portrait still gives us a sense of the magnificence of the lynx-lined coat that was popular among rich Venetians during that time.
Unfortunately, the painting is damaged in many areas, and we can't see it as clearly as Titian intended. But what's left of it is still an incredible example of his skill as a painter.
Portrait of Girolamo Fracastoro hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.