The historic Biblioteca Ambrosiana on Tuesday unveiled 280 drawings by such masters as Raphael and Leonardo da Vinci collected by a 17th-century friar that have just returned from a Florence studio where they were restored for years.

The so-called “Codex Resta,” a collection of drawings named for the friar Sebastiano Resta who assembled it, was returned to the library this week in five specially designed crates — seven years after the volume made the journey to Florence in a trolley suitcase.

“This is a measure of the operation,” said Cecilia Forsinini, director of restoration at the Florence-based state conservation institute, Opificio delle Pietre Dure. Inside the containers were smaller boxes to provide more suitable storage for the delicate drawings, and allow them to be consulted and viewed without causing further harm, Forsinini said.

Much of the damage to the drawings in the “Codex Resta” was caused by the binding: some drawings had inadvertent folds, some had wrinkles, and all of the pages, each containing up to two drawings, were wavy.

The drawings were first unbound from their worn leather binding, and then each received individual treatment depending on its condition, from cleaning to repairs. Milan's Biblioteca Ambrosiana plans to display the collection with other treasures in the future, but no date has been set. It is currently showing the first of 24 exhibits spanning six years that will display all of Leonardo da Vinci's 1,119-page “Codex Atlanticus.”

Resta collected some 3,500 drawings in some 30 volumes in his lifetime.

Only six volumes remain in tact, including the “Codex Resta” and another of Peter Rubens' drawings at the Biblioteca Ambrosiana. But individual drawings, distinguished by the collector's numbering, have made their way into public and private collections round the world.