The Early Renaissance bridges the art period during the fifteenth century, between the Middle Ages and the High Renaissance in Italy. The "Early Renaissance" was all about Florence. Firenze, as it's known to those who live there, was the place in which to launch one's artistic career in 15th-century Italy. Florence ushered in the 15th-century with what we'd now refer to as a "juried" competition in sculpture. There was, and is, an enormous cathedral in Florence known as the Duomo, whose construction was begun in 1296 and continued for nearly six centuries. Adjacent to the cathedral is a separate structure called the Baptistery, whose purpose, obviously, was for baptisms. In the 14th-century, the Proto-Renaissance artist Andrea Pisano executed a pair of immense bronze doors for the east side of the Baptistery.
These were modern wonders at the time, and became quite famous. So successful were Pisano's original bronze doors, the Florentines decided it would be a great thing entirely to add another pair to the Baptistery. To that end, they created a competition for sculptors and painters. Any talented artist was welcome to try his hand at the assigned subject, a scene depicting the sacrifice of Isaac, and many did. During the Early-Renaissance art period, the Church stabilized and unified once again under one Pope, provided artists and architects with a seemingly endless supply of subject material.