After the death of Maximilian III in 1618, Archduke Leopold V was appointed imperial representative of Tyrol and of the Upper Provinces. Like his predecessor Maximilian, Leopold V put his trust in Father Scheiner. Scheiner's ""Oculus hoc est: Fundamentum opticum,"" containing many new insights into the physiological nature of the eye, was published in Innsbruck in 1619. The book had been written earlier in Ingolstadt. "Oculus" is subdivided into three parts: the first part treats the anatomy of the eye, the second part the refraction of the light ray inside the eye, and the third part deals with the retina and the visual angle. Scheiner once again chooses the way of observation and experiment. Like Kepler before him, he found that the retina is the seat of vision and that the optic nerve transmits the images from the retina to the brain. Scheiner was rebuked once more for going from Innsbruck to Hall in a heavily loaded coach drawn by six horses! Father General Vitelleschi wrote him a letter. Archduke Leopold V and Father Scheiner carried on a sizeable correspondence from 1620 until 1632. One of Scheiner's letters to Leopold from 1626 informs the Archduke that Galilei is not to hear of Scheiner's work concerning the sunspots.