This work is devoted to the complex problem of the idea of the united Caucasus. Three political entities (Georgia, Armenia, Russia) and their churches were involved parties. The Evolution of this idea revealed the different kind of interests of the involved parties. In most cases their attempts were unsuccessful, though in some periods we can observe more realistic approach to the problem as it had been in the epoch of David the Builder (XI-XII c.c.), signifying the classical example of implementation of the idea of the United Caucasus.