* Early forms of oversight: While not formal inspections in the modern sense, some forms of oversight of schools existed centuries ago. Religious authorities, for example, often monitored church schools to ensure doctrinal adherence.
* 19th Century: This is when more formalized inspection systems began to emerge in several countries, notably in Europe. For example, in England and Wales, the beginnings can be traced to the 1839 Committee of Council on Education, which led to the appointment of inspectors to monitor schools receiving government grants. Other countries also started developing their own inspection systems around this time, often driven by a desire for standardization and quality control.
* 20th and 21st Centuries: The 20th and 21st centuries saw the widespread adoption and refinement of school inspection systems globally. The specific dates of implementation and the methods employed varied considerably based on individual countries' educational structures and philosophies.
Therefore, there's no single answer to "when schools were first inspected." The process evolved gradually over time, with the 19th century marking a significant turning point in the development of formalized inspection systems in many parts of the world.