The italian renaissance spread across europe in the late 1400s through?

Northern Italy had commercial success. Trade would have played a big part in this. The ideas of individualism, humanism, and secularism interested many people of the time, mainly because the ideas were so different from the "focus-on-God" idea of the Dark Ages (a time of much death because of war and disease, and very little education - not remembered well). The ideas of the Renaissance were taken from the Greco-Roman time period, a time of much enlightenment. Italian trade with Northern countries would have spread these ideas. The development of the printing press and moveable type enabled books to be printed quickly and spread around much more easily than previously, which meant that new Renaissance ideas were widely read and easily discussed.