Children have been fighting in wars throughout recorded history. In ancient times, children were often trained in military skills and sent to fight alongside adult soldiers. In the feudal era, children from noble families were often sent to fight in wars as a way of proving their loyalty to their lord. In the Early Middle Ages, the age to join the army of the Kingdom of England was 12. Later, the modern draft age of 18 started to be imposed in countries such as the United States and France after World War I. However, children as young as 16 have been admitted into modern military forces. In the United States, it was not until 1971 that the military raised its minimum recruitment age to 17 and not until 1982 that it raised the minimum age to 18. During the Vietnam War, approximately 250,000 U.S. soldiers fighting were under the age of 18. It is estimated that between 1982 and 1990, about 20,000 minors may have joined the military with falsified documents. Nevertheless, the International Labour Organization (ILO), with the support of various international organizations and national governments, has been able to raise the minimum age of admission into the military forces in many countries to 18 years. There are still 20 countries around the world that deploy child soldiers.