During the Iron Age, Central, Western and most of Eastern Europe gradually entered the historical period. Greek maritime colonization and Roman terrestrial conquest form the basis for the diffusion of literacy in large areas to this day. This tradition continued in an altered form and context for the most remote regions (Greenland and Old Prussians, 13th century) via the universal body of Christian texts, including the incorporation of East Slavic peoples and Russia into the Orthodox cultural sphere. Latin and ancient Greek language continued to be the primary and best way to communicate and express ideas in Liberal arts education and the sciences all over Europe until the early modern period.