The Greeks of the Classical era made several notable contributions to science and helped lay the foundations of several western scientific traditions, like philosophy, historiography and mathematics. The scholarly tradition of the Greek academies was maintained during Roman times with several academic institutions in Constantinople, Antioch, Alexandria and other centres of Greek learning while Eastern Roman science was essentially a continuation of classical science. Greeks have a long tradition of valuing and investing in paideia (education). Paideia was one of the highest societal values in the Greek and Hellenistic world while the first European institution described as a university was founded in 5th century Constantinople and operated in various incarnations until the city's fall to the Ottomans in 1453. The University of Constantinople was Christian Europe's first secular institution of higher learning since no theological subjects were taught, and considering the original meaning of the world university as a corporation of students, the world’s first university as well.