Leiden University Library opens its doors after its founding in 1575.

Leiden University Libraries is the set of libraries of Leiden University, founded in 1575 in Leiden, Netherlands. Holdings include some five million volumes, one million e-books, ninety thousand e-journals, two thousand current paper journals, and three thousand cuneiform tablets. The library manages large collections on Indonesia and the Caribbean, and curates seven entries in UNESCO's international and Dutch Memory of the World Register. Joseph Justus Scaliger, who was a languages and history professor at Leiden from 1593 up to 1609, commented in Latin on the library:

"Est hic magna commoditas bibliothecae ut studiosi possint studere"

—Josephus Justus Scaliger

"Here [at Leiden] is the great convenience of a library so that those who want to study [students], can study."

Year 1575 (MDLXXV) was a common year starting on Saturday of the Julian calendar.