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.
Middle Ages - Children's Encyclopedia (Ages 8-11) The Middle Ages was the period in European history that came between ancient and modern times. It lasted from about AD 500 to about 1500. The Christian church played an important part in the history of the Middle Ages.