Most accounts translate it to: The ass arrives, beautiful and most brave. From the 13th century song "Orientis partibus"; quoted in Nietzsche's copy of Georg Christoph Lichtenberg's Vermischte Schriften (Miscellaneous Writings).
What does it mean?
Its meaning isn’t immediately obvious, so here’s a clue. It comes right after this line: There is a point in every philosophy at which the “conviction” of the philosopher appears on the scene[.]
So the donkey is this ‘conviction’. Nietzsche’ is saying all who philosophize eventually wind up revealing their comically unphilosophical self-delusion, its embarrassing history, and the farcical underpinning of all their work. - Anarchycreek.com
See Nietzsche's Writings as a Student with essays and autobiographical works written from 1858-1868. Available with English translations, explanatory notes, sources and 61 color illustrations.
Get Tips for Learning Latin with Less Stress from Latin Alive!
Here are 20 Latin Phrases You Should Be Using from Mental Floss.