This is a 1523 portrait of Erasmus of Rotterdam by Hans Holbein the Younger (1498 – 1543). Same tripod grip we use now although we don’t much use the incline. The close up shows the grip and pen with greater clarity. That doesn’t look like a quill though. It’s either an early MYU or perhaps a reed?
H. Doug Matsuoka etcetera 
Early MYU! 😀