How did the ideas of the Italian Renaissance spread to northern Europe?

In the fifteenth and sixteenth centuries, many northern humanists, such as Erasmus of Rotterdam, Nicolaus Copernicus, Heinrich Agrippa, and Thomas Linacre, spent time in Italy and sometimes studied in Italian universities. During the same period, many wealthy German, English, Flemish, and French merchants often visited Italy for business purposes and maintained extensive networks of Italian contacts. Similarly, many painters, such as Albrecht Durer, stayed in Italy for years in order to learn the latest advances in painting. Humanistically educated courtiers and rulers of the time visited Italian libraries, museums, and artists’ studios. During one such visit, the Emperor Charles V picked up the brush of the famous Venetian painter Titian from the floor and respectfully returned it to the artist.
The Italian humanist scholars of the period maintained a lively exchange of news and ideas with their northern colleagues. Italian humanist printers, such as Aldus Manutius of Venice, sold critical editions of the Greek and Latin classics to northern European customers. Some Italian merchants, such as Van Eyck’s client, Giovanni Arnolfini, lived in Flanders and other European countries and their tastes influenced Northern painting. Italian artists likewise worked in many European countries and shared their experiences with the locals. For example, Francis I invited Leonardo da Vinci to move to France, and in response to this invitation, the great painter came and spent his last years there.
The Italian Renaissance also influenced certain northern religious thinkers. Erasmus, Thomas More, John Calvin, and Philip Melanchthon came up with their own approaches to Renaissance thought, in which they focused on Christian religious, philosophical, political, and ethical topics (Christian humanism) instead of classical mythology and literature. In this way, they connected the Renaissance to the Protestant and Catholic reformations.