The number of Serbian manuscripts dating between the 12th and 17th centuries that are located outside Serbia is estimated at 4,000–5,000. The largest number of the manuscripts are located in Europe. The largest and most important collection is housed at the Hilandar on Mount Athos. Next, the second largest collection is most likely found in Russia, where hundreds of manuscripts are held. More than a thousand of medieval manuscripts were destroyed during the German bombing of Belgrade (1941). The Digital National Library of Serbia (NBS) has digitalized several manuscripts, included at their website.