Edward was only 9 years old when he became king. Because of his youth, he had two advisors. The first was his uncle, the Duke of Somerset, who became Lord Protector, and for the first two and a half years of Edward's reign, Somerset advised and guided the young king. Somerset was replaced by the Duke of Northumberland. Both men wanted major changes made to England's religion. As a result of their advice and Edward's beliefs, Edward's reign is mainly remembered for the changes made to religion while he was king. During Edward's reign, major religious changes did occur that had not penetrated during his father Henry VIII's reign.
Laws were passed to make churches more plain. Catholic churches were rich in decorations and color. Now under Edward, stained glass windows and pictures were removed from churches; the furniture within churches became very basic. The actual services were made linear and the common person could no understand what was being said as services -- now called Holy Communion -- were in English. Archbishop Cranmer wrote a prayer book also in English. Priests did not have to dress in the bright clothing associated with the Catholic Church and under Edward, they were allowed to marry. The king remained as head of the church.
All of these changes were a major break from what the Catholic Church had been like. In parts of Germany and Switzerland, religious groups had also broken away in protest against the wealth and corruption of the Catholic Church. They become known as Protestant, and England under Edward, became a Protestant country with a Church of England.
Edward had never been a healthy boy and his health failed in 1553. A nine day interruption of the 'queen-who-never-was', Lady Jane Grey, his half-sister Mary became queen of England and the country went through another spell of religious changes.
Winchester City Mill Museum