According to historical documents, first attempts to separate children crime to the independent jurisdiction were taken in the time of Roman law, 6th century BC.
The history of modern Juvenile Justice has begun in 16-17th centuries. Although children were prosecuted as the adults, some documents indicates that some courts  took in account the young age of offender and meted out more lenient punishment. In the 18th and 19th centuries the reformatories (House of Refuge in he USA) were created in many western countries. Their founders hoped that Christian values can change youth and tried to to use labor and education as the corrective measures for young criminals. However this attempt was unsuccessful, reformatories turned to youth prisons.
Training schools have impacted on schooling and vocational training significantly. First state-operated training schools were opened in the middle of 19th century in the USA. The modern model of training school still remains the part of rehabilitative therapy.
First Juvenile Court was established in 1899 in Illinois and became the turning point in the history of Juvenile Justice. It has some fundamental differences from criminal court system: its primary aim was rehabilitation kindhearted supervision for children, not the punishment. At the beginning of 20th century Juvenile courts appeared in the majority of European countries, though in every country it have obtained the specific features.
In the 1940th the mass construction of “rehabilitation facilities” for juvenile delinquents began in the USA.
In the middle of 1960th the number of Supreme Court decisions structured juvenile courts and made them more similar to adult courts. Today, almost the half of century later, the Juvenile Justice is considered as ineffective one and needs another revolutionary reform.