Hello,
I hope it is okay that I ask this question here. I do not like to bother my professor too much, so I thought I would ask this here: How do you say “happy birthday” in Ancient? They may not have said this, so perhaps I could say: “You have a happy day of birth”
Thank you so much in advance,
TJ
Συγχαίρω σοι ἐπὶ τοῖς γενεσίοις σου (I congratulate you with your birthday). Maybe there are other variants.
I like Vladimir’s suggestion. Here are a few more:
In Modern Greek, you say χρόνια πολλά
http://www.youtube.com/watch?v=jiQEKSuXiB0
the ancient form of which might be something like χρόνοι πολλοὶ (γένοιντό) σοι! The ancient word for birthday was ἡ γενέθλιος ἡμέρα, so καλὴ γενέθλιος would work. You could also say καλῶς γενεθλιάζοις. “(may you celebrate your birthday well.” How about μακάριος (μακαρία) σὺ γένοισο ἐν τῇ γενεθλίῳ σου? There are always multiple ways of saying something in any language, and this is especially true for Ancient Greek. Maybe just καλὴ ἡ σὴ ἡμέρα!
Anyone else have any ideas?
Or rather εἰς πολλὰ ἔτη? By the way, it is just what they sing in the Orthodox church to a bishop celebrating liturgy.
Oh my, thank you so much! This is great 
I wasn’t sure if I would get a reply, and just in time.
Thank you all very much, I will work with these suggestions!
TJ
It cannot be found with this meaning in the TLG.
Καλὰ (εὖ) γενέθλιά σοι εἴη, bonus dies natalis sit tibi.
It also depends on the kind of Greek one wants to use. So far as I understand, in classical Greek τὰ γενέσια (the word I used) meant rather “anniversary of sb’s death”. So if it is necessary to say “happy birthday” in classical Greek, it would be better to use τὰ γενέθλια in order not to be understood as “Happy anniversary of your death”. 
But if the Koine is quite acceptable, τὰ γενέσια is an excellent word, too.