The three-day conference of religious leaders will start July 16 in Madrid.
By Caryle Murphy | Correspondent of The Christian Science Monitor
The 200 invitees included vocal critics of Islam, notably the Rev. Franklin Graham, a conservative Evangelical who has called Islam an "evil and wicked" religion. He cannot attend because he is preparing for a trip to North Korea, a Graham spokesman said.
Former Vice President Al Gore and the Archbishop of Canterbury were also invited, but declined because of prior engagements, their offices said.