The internal energy and temperature of a system decrease (E E. The System and Work. The system is usually defined as the chemical reaction and the boundary is the container in which the reaction is run. In the course of the reaction, heat is either given off or absorbed by the system.
The Middle Ages began in the year 476 A.D. and ended around 1300 with the beginning of the Renaissance. The Middle Ages, also called the Medieval Period, began just after the fall of Rome and it dominated the European continent through the early 14th century. The Middle Ages filled a time period between the ending of a great reign and the beginning of a new era characterized by revitalization and cultural growth.
According to most historians, the Middle Ages began with the fall of the Roman Empire in 476 A.D. and ended with the beginning of the Renaissance in the 13th, 14th or 15th century A.D. Keep Learning.