Both Middle ages, Italian Renaissance and Northern Renaissance reflect the worldviews of the times. Differences between them are given by the distinct ways each of them dealt with the place of the human being in the cosmos.
In Middle ages art was mainly about religious themes and had an educational role in spreading catholich worldview when most people couldn't read and had little or no access to cultural exchanges that happened in places like cities. Art represented the greatness of God, was characterized by moral teachings inspired by the Bible and by the lives of the saints. Painting had no sense of perspective, that is, it had no depth; painted scenes had no horizon and there wasn't an attempt to realistically depict human body.
Italian Renaissance, on the other hand, pertained to a context where cities were already central spaces full of movement. These city-states had rich families (like the Medici family) fighting for power who'd exhibit themselves through financing of great artists, creating what we call the mecenae. Italian Renaissance valued Classical Greece, it's authors and political ideas, inspired by the intellectual effervescence of that moment. Admiration for Classical Greece made humanist ideas and intellectual exploration from the human point of view one of the main characteristics of this movement. There was also a close relation with scientific concepts, so artists from this time were concerned with proportion and anatomy.
Northern Renaissance hadn't such close relation to the rich. Paintings by it's principal artists, like Jan van Eyck (1390-1441), different from the Classical Greece motifs largely utilized in Italian Renaissance art, represented peasants' daily lives and domestic interiors with naturalistic tones.
