"About 400 members of the Archdiocese of Los Angeles are en route to Rome for the bestowal of the Pallium upon Archbishop Jose H. Gomez, the Archbishop of Los Angeles, by Pope Benedict XVI on June 29, the feast of Saints Peter and Paul.
But what is the Pallium? It is a circular band about 2" wide, worn about the neck and having two pendants--one hanging down in front and one behind. It is worn over the chasuble at Mass. Every February two lambs are blessed each year and their white wool is used to make the Pallium. The wool is presented to the Pope, and Sisters then make the Pallium for the new Archbishops.
Who wears the Pallium? The Pallium is worn by Archbishops who are also Metropolitan Archbishops--they head up a Province of Dioceses. Archbishop Gomez is the Metropolitan Archbishop of the Province of Los Angeles, and he presides over the Archdiocese of Los Angeles directly, and indirectly, over the Dioceses of Monterey, Fresno, San Bernardino, Orange, and San Diego.
Interesting: even though Archbishop Gomez served as the Archbishop of San Antonio and wore the Pallium there, if he is transferred to a different Metropolitan Archdiocese, he is required to receive a new Pallium. The former Pallium is placed in his casket upon his death and Funeral Mass.
The new Palliums are solemnly blessed on the eve of the feast of Saints Peter and Paul, and are kept in a special silver-gilt container in front of the Main Altar in St. Peter's Basilica.
It is not clear when the bestowal and use of the Pallium began in our Church. However, the first mention of the Pallium being used is in the first half of the 4th century--a long time ago. Pope Marcus, who died in 336, conferred the right to wear the Pallium on the Bishop of Ostia, near Rome. The wearing of the Pallium was more common in the 5th century.Read the rest here.