IVANOBA

1. In Megrelian ivanoba means June, which is considered to be in honor of John the Baptist, despite that not only the month of John's birth is unknown, but neither the year.
2. June is the month of Ivan Kupala pagan holidays (summer solstice), celebrated, in particular, in Ukraine, but never celebrated in Megrelia:
http://ka.wikipedia.org/wiki/ივან-კუპალა
3. Ivan is considered to be a Biblical name derived from Yohanan, but...
4. The patronimic Ibáñez existed in Spain already in times of Don Pelayo (VIII century), only three hundred years after Spain became Christian:
http://heraldicablog.com/2008/03/30/ibanez-escudo-heraldico/
5. The name Iban is Basque. And we know that Basques are the nation that preserved their national identity (including language) from the pre-Indoeuropean times, let alone pre-Christian epoch. Even when it's not considered Basque, it's considered Germanic (obviously, pre-Christian):
“Nombre: San Iban; Fecha onomástica de este santo: 16 de mayo; Explicación del nombre Iban: Germanico”.
http://www.aniversalia.com/santo-de-san-Iban-6003-I
6. If Megrelian ivanoba is a tribute to Ivan Kupala, not John the Baptist, then the only place where Megrelians could have seen the celebration of the solstice was ancient Ukraine, where someone named the local rivers with Kartvelian names. If it happened indeed it happened long b.C.
7. And now the most exciting. Everyone knows about an akward tradition of writing V instead of U in Latin texts. Like this:

                                Llivia. Photo of Kartvelian History & Language Research Center

It had no chances of not leading eventually to confusions between the two letters. One of such possible confusions may be the clue to solving the 'ivanoba' mystery.

The Numa's calendar (713 b.C.) already mentions Iunius among the months:
http://en.wikipedia.org/wiki/Roman_calendar

The word's origin is unclear. Ovid alone suggests several interpretations:
http://en.wikipedia.org/wiki/June

And now compare Iunius to  its Kartvelian counterpart ივნისი [ivnisi]. Given the abovementioned confusion 'V-U', we have a complete coincidence: IVNI - IVNI (-us and -si are flexions and suffix). Which makes it reasonable to consider ivanoba a derivation from pre-Christian Ivan Kupala, which is an indirect proof that Megrelians witnessed Ivan Kupala celebrations with their own eyes in Ukraine (or celebrated it themselves while living there).