How was "man" discovered during the Renaissance?
As the term Renaissance means "rebirth," the period of history with this name saw the resurgence of the arts and science and diplomacy. In the Renaissance, man was "discovered" as a polymath, a person of expertise in many areas. The consummate Renaissance men, then, are the polymaths, Leonardo da Vinci and Michelangelo.
Leonardo da Vinci was an artist and an inventor who created many designs for what later became machines in the nineteenth and twentieth centuries, machines such as the tank, machine gun, airplanes, and helicopters. His keen sense of aerodynamics led DaVinci to design these machines that could not even be produced in his age.
As a sculptor and architect, Michelangelo is unsurpassed in creative genius. His talent as a painter, too, is evinced in his renderings on the ceiling and upper walls of the Sistine Chapel, especially the creation. Michelangelo pioneered the Mannerist style of architecture, in which there are elongated proportions, much style, and lack of specific perspective. Thus, through his artistry and the artistry and creativity of Leonardo da Vinci, man saw the world anew; he was reborn into new ideas and new art.
I love your question. Man was discovered during the Renaissance in two ways. A little context is necessary to make this point.
Before the Renaissance, the church pretty much held sway. For this reason, man was not at the center. It was the church or we can say God. Man was considered secondary. This feeling was enhanced further by the great accomplishments of the classical world, of which people fell short.
In light of this, when the Renaissance came to be, there was a sense of the greatness of man. Great works were done and there was a feeling that they could outshine even the classical world. In his sense, man was rediscovered, that is, human potentiality was rediscovered.
Second, people began to question the church. In light of this, the Protestant Reformation would not have been possible apart from the Renaissance. In this sense, man began to be the measure of all things. Man was back on the map, as it were.