Christopher Clavius

Jesuit mathematician and astronomer who reformed the calendar under Pope Gregory XIII and wrote the influential Commentarius in Sphaeram.

Works

• Gnomonics
• In Sphaeram

Chapter I (The Six Days of Creation)

• Verse 14: Let There Be Lights in the Firmament — Cited via Voellus on the etymology of "hour" from the Hebrews

  "from Fr. Clavius our Voellus, book I On Horology, ch. 1"

• Verse 16: And God Made Two Great Lights — Cited from his Sphere, ch. 1, on the size of the moon

  "Fr. Clavius in his Sphere, ch. 1"

• Verse 16: And God Made Two Great Lights — Cited for all the astronomical calculations

  "These and more things Fr. Christopher Clavius teaches in his Sphere, ch. 1."