After 1517, when the new invention of printing made these texts widely available, the Dutch humanist Erasmus, who had studied Greek at the Venetian printing house of Aldus Manutius, began a philological analysis of the Gospels in the spirit of Valla, comparing the Greek originals with their Latin translations with a view to correcting errors and discrepancies in the latter. What text no longer remains without the type of thorough review that others texts had received by the 12th century?