By Dan Collyns
BBC News, Lima
Chile has returned almost 4,000 books to Peru's national library, more than a century after they were taken by Chilean soldiers.
The books have gone on display in Lima
The soldiers pillaged the library after capturing the Peruvian capital, Lima, in 1881, during the War of the Pacific.
Exactly 3,778 books were returned to Peru's national library - and there was no talk of a fine.
But it is hoped that the return of the books may go some way to improving the two nations' tetchy relations.
Peru's foreign minister said the move would strengthen bilateral relations.
Chile's director of Libraries, Archives and Museums said it signalled a deep commitment to building a relationship of brotherhood between the two countries.
Relations have been strained ever since the books - 2,500kg (5,500 lbs) of them - were stolen by Chilean soldiers occupying Peru's capital more than 120 years ago.
In the war, which lasted from 1879 to 1883, Peru lost territory and neighbouring Bolivia lost its coastline.
The theft of the volumes - written in Greek, Latin, French and Spanish, many dating back to the 16th Century - is an example of how, historically, many Peruvians see their neighbours to the south.
Chile's Michelle Bachelet has been a target of Peruvian hackers
In their view, whether it is territory, maritime borders or pisco (brandy), the Chileans, at some point, stole what was rightfully Peruvian.
While the countries' governments are probably friendlier than they have ever been, there is still a perennial dispute over maritime borders which Peru has threatened to take to the International Court.
There is also ongoing rivalry in cyberspace as Peruvian and Chilean hackers battle to post patriotic messages on each other's government websites.
Last week, a Peruvian flag with the message "Long live Peru", followed by an expletive, was posted on the official website of Chilean President Michelle Bachelet.
It will take more than a return of a few library books to quell the countries' historic rivalry.