There is more to the definition of parable than a "(symbolically) ficticious narrative." Proverb and parable both derive from the same Hebrew & Greek root words.
Can a literal historical event also be applied as a spiritual parable/proverb? I believe that common thread reasonates all through the OT & NT.
One example is Peter denying Christ, it happened, what spiritual lesson (parable/proverb) is contained? All the elect or chosen have done this (denied the Lord by losing their first love) and have had to bitterly repent. There are thousands more examples starting at Genesis.
parable 4912
H4912
משׁל
mâshâl
maw-shawl'
Apparently from H4910 in some original sense of superiority in mental action; properly a pithy maxim, usually of a metaphorical nature; hence a simile (as an adage, poem, discourse): - byword, like, parable, proverb.
parable 3850
G3850
παραβολή
parabolē
par-ab-ol-ay'
From G3846; a similitude (“parable”), that is, (symbolically) fictitious narrative (of common life conveying a moral), apoth gm or adage: - comparison, figure, parable, proverb.
parable 3942
G3942
παροιμία
paroimia
par-oy-mee'-ah
From a compound of G3844 and perhaps a derivative of G3633; apparently a state alongside of supposition, that is, (concretely) an adage; specifically an enigmatical or fictitious illustration: - parable, proverb.
The following are the definitions of the definitions
adage
a condensed but memorable saying embodying some important fact of experience that is taken as true by many people [syn: proverb]
maxim
1. an expression of a general truth or principle, esp. an aphoristic or sententious one: the maxims of La Rochefoucauld.
2. a principle or rule of conduct.
metaphor
A figure of speech in which a word or phrase that ordinarily designates one thing is used to designate another, thus making an implicit comparison, as in "a sea of troubles" or "All the world's a stage" (Shakespeare).
One thing conceived as representing another; a symbol: "Hollywood has always been an irresistible, prefabricated metaphor for the crass, the materialistic, the shallow, and the craven" (Neal Gabler).
simile
A figure of speech in which two essentially unlike things are compared, often in a phrase introduced by like or as, as in "How like the winter hath my absence been" or "So are you to my thoughts as food to life" (Shakespeare).
I hope this helps,
Joe