Prime Minister Mariano Rajoy took part Sunday in the ceremony during which the Calixtino Codex, which was recovered by police last week, was returned to the cathedral in the northwestern Spanish city of Santiago de Compostela.

The extremely valuable 12th-century manuscript, which was stolen last year from the cathedral, was recovered on Wednesday.

The five-volume Codex Calixtinus, which extols the virtues of St. James the Apostle, "has an owner, but we all feel that it belongs to us," Rajoy said.

The Historical Heritage Institute should "check out" the condition of the codex, which was stored "in very deficient conditions" in the town of Milladoiro, a few kilometers from the cathedral, where it was stolen in July 2011, the prime minister said.

"The Calixtino Codex is a type of guide for all pilgrims," Rajoy said, adding that he was placing himself at the service of the archbishop to "make a major effort to prevent these things from repeating themselves."

The codex "is back in its proper place" and "no effort will be spared" in terms of security going forward, Santiago de Compostela Archbishop Julian Barrio said.

Manuel Fernandez Castiñeiras, an electrician who worked at the cathedral for many years, confessed to stealing the codex and remains in jail.

The codex was found in the garage of a building in Milladoiro, where several people were arrested in connection with the theft.

Police found the codex wrapped in trash bags in Fernandez Castiñeiras's garage.

Fernandez Castiñeiras, his wife and son were arrested on Tuesday in connection with the robbery, and the son's girlfriend was arrested later.

The son and his girlfriend were released from custody on Thursday.

Fernandez Castiñeiras, who worked at the cathedral for 25 years, had keys to the church, sources close to the investigation told Efe.

The Codex Calixtinus is composed of five volumes with a variety of themes, but its singular objective was to extol the virtues of St. James the Apostle, whose remains were said to have been found in Santiago de Compostela in an urn some eight centuries after his death.

The missing illuminated manuscript is considered the oldest and most complete original copy of the Codex Calixtinus; 200 others are distributed across Europe in the Spanish cities of Barcelona, Madrid and Salamanca, as well as in Lisbon; London; Pistoia, Italy; and the Vatican.

The most well-known and most frequently translated of the five volumes is the last, which served as a guide for the medieval Way of St. James pilgrim and describes the route, its towns and cities, its people and customs, and shrines that should be visited. EFE