The exhibit opens to the public Sunday and runs through Nov. 9 in Birmingham before traveling to the San Francisco Museum of Art, where it will be shown Nov. 15 to Jan. 4.
It includes 11 drawings and Leonardo's Codex on the Flight of Birds, an 18-page notebook which had never been shown in the United States. Thick magnifying glasses are available for visitors to truly get a sense of the detail Leonardo packed into the drawings, some of which are nearly complete and others that seem like quick doodles.
"It's the first time that virtually every single Leonardo in this collection has traveled, so that added to the trepidation," Biblioteca Reale director Clara Vitulo said through an interpreter. "The collection of Leonardos is the most important collection for the Reale."
The group of drawings is the latest coup for the Birmingham museum, which hosted a 15-week blockbuster Pompeii exhibit last year.
Director Gail Andrews said the Leonardo show, which cost more than $420,000, will be free. She hopes that will draw more people to see what could be a once-in-lifetime event.
Knowing that Birmingham has been entrusted with some of Italy's treasures is humbling, she said.
"We're not so much nervous that something would happen, but just very aware of the magnitude of this project. Any museum in the world would be proud to have this exhibition," Andrews said.
After their San Francisco run, the drawings will return to Italy and be stored for at least a year as part of the preservation process, Vitulo said.
Two drawings that aren't included from the Reale are Leonardo's self portrait, which was deemed too fragile to travel after its 2003 showing at the Metropolitan Museum of Art in New York, and the Battle of Anghiari, which was already committed to another show.
The exhibit would not have been possible without specially designed frames to hold each page in constant temperature and humidity. Rome's minister of culture was not comfortable with the works traveling otherwise, Vitulo said.
"Given the anxiety about lending the group as a whole, the minister of culture feels their priority is number one, preservation of the drawings and number two, to allow them to be shared," she said. "The works are their own ambassador for Italian arts and culture."