The imperial emblem crowned, supported by two saints (St Paul with sword and St Peter with key.
From: Faustinus, Presbyter, active 4th century. Gregorii Baetici heliberitanae sedis antistitis De Trinitate, Sive De Fide. Romae: in aedib. Populi Romani, 1575.
St. Peter, St. Paul, imperial emblem, printer's device