Joaquín Navarro-Valls, who served as the Vatican’s spokesman, papal adviser and strategic envoy during the long and historic tenure of Pope John Paul II, died on July 5 in Rome. He was 80.

The cause was pancreatic cancer, according to Opus Dei, the influential religious order to which Mr. Navarro-Valls belonged as a lay member.

That religious connection was critical to his joining the Vatican in 1984, as was his background as a Spanish journalist and his role, at the time he was hired by the first non-Italian pope since the 1520s, as the president of Rome’s Foreign Press Association.

During the 22 years Mr. Navarro-Valls ran the Vatican press office, of which he was the first lay leader, he sought to internationalize and modernize the communications of an institution that was often seen as stuffy and insular.