ROME (Reuters) - Pope Benedict led a traditional religious procession through the streets of Rome on Thursday and called on Catholics to look beyond differences like nationality and social class to the common faith that unites them.

The 81-year-old Pope led the Corpus Domini procession from the Basilica of St. John's in Lateran to the Basilica of St. Mary Major, the two most popular churches in Rome after St. Peter's at the Vatican.

In his sermon at the Mass at St. John's before the start of the procession, the Pope said that communion joined all

Catholics together -- regardless of their backgrounds.

"We are united beyond our differences of nationality, profession, social class, ideas," he said.

The feast of Corpus Domini is known as Corpus Christi in some countries.

Benedict rode in a special vehicle along the procession route while kneeling before a monstrance, a gold and glass case containing a consecrated communion host.

(Writing by Phil Stewart; Editing by Jon Boyle)