Do you want to hear about Latin? Because I can give you my favorites in Latin. There's certainly older stuff, but this is fun.

First, there's the Pompeii graffiti. Some of the choicer bits:

• Weep, you girls. My penis has given you up. Now it penetrates men’s behinds. Goodbye, wondrous femininity!

• Amplicatus, I know that Icarus is buggering you. Salvius wrote this.

• Lesbianus, you defecate and you write, ‘Hello, everyone!’

• Theophilus, don’t perform oral sex on girls against the city wall like a dog

• I have buggered men

Let's go with the dirtiest poem ever, Catullus 16. Others have pulled their punches here, so the translation is mine:

I will ass-rape and skull-fuck you

Aurelius the fag and Furius the pedo,

You who judge me based on my verses

which are soft and insufficiently chaste.

For it is right for the pure poet to be pious.

He should, but his verses needn't,

which indeed have wit and charm

when they are soft and insufficiently chaste

and can arouse one's flesh and I'm not just talking

about in boys, but in you dirty, hairy old men

who can no longer even get it stiff.

And you, because you read about many

thousands of kisses think me unmanned?

I will ass-rape and skull-fuck you.

Hope that helps :-)

hi! I don't recall offhand whether any of these threads identifies the earliest, but take a scan through this section of the FAQ* for many examples:

Insults, Swears, and Curse Words

*see the link on the sidebar or the wiki tab

Not exactly a profanity, but was found in the Queops pyramid's stones some cheerful graffiti written, presumably, by some workers. In one of them you can read: "how drunk is the king?". This story is well known but, unfortunatly, I could never find its primary source (if exists). This anecdote appears in both Lionel Casson 's "Ancient Egypt" and Dales Davis' "Civilizations in history".