PAL

Ptolemaeus Arabus et Latinus

_ (the underscore) is the placeholder for exactly one character.
% (the percent sign) is the placeholder for no, one or more than one character.
%% (two percent signs) is the placeholder for no, one or more than one character, but not for blank space (so that a search ends at word boundaries).

At the beginning and at the end, these placeholders are superfluous.

Ptolemy, Almagesti (tr. Erasmus Reinhold)

Wittenberg, Johannes Lufft, 1549 · 44v

Facsimile

ΠΤΟΛΕΜΑΙΟΣ

Οἶδʼ ὅτι θνητὸς ἔφυν, καὶ ἐφάμερος, ἀλλʼ ὅτʼ ἂν ἄστρων
ἰχνεύω κατὰ νοῦν ἀμφιδρόμους ἕλικας,
οὐκέτʼ ἐπιψαύω γαίης ποσίν, ἀλλα παρʼ ἀυτῷ
ζηνί διοτρεφέος πίμπλαμαι ἀμβροσίης.