Sir Peter Lely was Dutch by birth, but his career was nearly all spent in England, where he became the dominant portrait painter to the court. This is one of the few violin-player paintings I have found from England as early as the middle of the 17th century. A very low violin hold (awkwardly near the middle of his body!), an easy bow hold, and although you can't see his right thumb, the placing of his fingers suggests to me an on-the-stick position. Once again, notice the short bow - and the bridge at the bottom of the f-holes.