A female American professor once told an Orthodox clergyman the desire of the Pope to invite Elder Paisios and Elder Porphyrios to the Vatican. The response of both was the following:
"No, we cannot go. Because the Roman Catholic Church and the Pope are not ready. They have very much egoism. They not only want to subjugate us, but they do not believe we have the truth. There is no need to go. We would better help the situation by our prayers."
Source: Translated by John Sanidopoulos