Final answer:
The first European state to mandate compulsory elementary education was Prussia, setting a historic precedent and influencing education systems worldwide.
Step-by-step explanation
The first European state to mandate compulsory elementary education is widely recognized as Prussia. This historic move took place in the 18th century, and it set a precedent for the development of state-controlled education throughout Europe. Prussia's education system set the stage for other reforms across various European nations, where states began to recognize compulsory education as a means to improve literacy and promote social cohesion.As for the impact of compulsory education, it led to a significant increase in literacy rates and educated citizenry, creating a foundation for the modern education systems we see across Europe today. Notable developments in other countries, such as Horace Mann spearheading education reform in the United States and Japan establishing a public school system, were influenced by this foundational educational model.In conclusion, compulsory elementary education as a state mandate began with Prussia, which was the catalyst for what became a widespread commitment to public education across the European continent and beyond.