Palestinian leader Mahmud Abbas (C), Pope Francis (L) and Israeli President Shimon Peres (R) plant an olive tree after a joint peace prayer on June 8, 2014 in the gardens of the Vatican. The Vatican has defined the meeting between Israeli President Shimon Peres and Israeli President Shimon Peres as an "invocation for peace" but has stressed it will not be an "inter-religious prayer", which would have posed problems for the three faiths. In the Vatican Gardens, the prayers will be recited in chronological order of the world's three main monotheistic religions, starting with Judaism, followed by Christianity and then Islam. AFP PHOTO / FILIPPO MONTEFORTE