Caesar Cipher

Here's an ode I preserved for you in a poetically postured pose, Particularly by my peculiarity of winding words with such prose. Avail to the thesauri, and lexically thy dexterity shall enhance, And uncover the meaning within this poem if you chance. If ye choose to not peruse the prose within this poesy parlance, A song I'll sing, a portrait I'll paint, or perhaps a jig I'll gaily dance. Hither reader! Why not absolve thyself from an abstrusely crafted code? For I warn that tedium and pomp onomasticon from thus unload. If ye choose to peruse the prose within my cryptic poem, Mind my method of muddling words to enclose what you must open. Acquiesce a cumpulsory capacity for cryptology, To bring from beneath what brews within this jambalaya of symbology. First you must learn what it means for words to be encrypted, A simple use of the alphabet on which the letters in words are shifted. Give each letter from A to Z a number; one to twenty-six: A mathematical use of Roman numeral, an ancient coding trick. Now write a sentence, plain words: plaintext, Try it now to learn what's next. The letter within a name, such as Aileen, Read: one, nine, twelve, five, five, fourteen. Pick a word: a key you use to change, The name Aileen to something strange. Now you must learn what it means for words to be decrypted, An ambitious mode to decode a code that an encryption has restricted.