Try to direct your attention to the headband he's wearing. I knit it for a friend, the Duke is just modeling it for us.
Yarn: I wish I could remember. I've lost the ball band. I do know it's 100% wool. Needle: US 7 Pattern: CO 100 sts, join, being careful not to twist your stitches work in stst for 5 in on RS purl 1 row work in stst for 5 more inches BO, catching the matching CO stitches to join the two ends