And some of the artworks needed major conservation work before they were fit for display.
One painting, the southern Italian Adoration of the Magi was almost black with dirt when it was sent to the restoration studio at Glasgow Museums Resource Centre.
Experts say it is now visible as a 'stunning early Renaissance masterpiece.'
The exhibition, Essence of Beauty: 500 years of Italian Art, sees masterpieces from Glasgow's treasure trove of Italian paintings being displayed together for the first time to mark the publication of a new catalogue of the collection.
The show includes works by some of the greatest names of Italian Renaissance and Baroque painting, including Bellini, Titian, Rosa and Botticelli.
But it also features decorative art, armour, sculpture, glass and rare ceramics to help visitors understand the range of objects created during the period.
Dr Ellen McAdam, Head of Glasgow Museums, said: "Our conservation team have been working for almost three years to ensure that these paintings – some of which have not been on display for more than a century – are back to looking their best."
Peter Humfrey, Professor of Art History at St Andrews University, said: "The exhibition offers an unprecedented opportunity to showcase Glasgow Museums' collection of Italian paintings. Although still too little known, it is among the most impressive of any in the UK."
Essence of Beauty, Kelvingrove Art Gallery and Museum, today - August 12. For information www.glasgowlife.org.uk/ museums