Henry VIII was the second son of Henry VII of Lancaster and Elizabeth of York, and the next king after Henry VII. His older brother Arthur was meant to be the next heir, except he died leaving Henry VIII as the Prince of Wales.
Henry became king at the age of 18 in 1509, and married his brother's widow, Catherine of Aragon, the daughter of Ferdinand and Isabella of Spain, the Catholic Monarchs.
Catherine was pregnant with a girl and was born, a few months later she became pregnant with a boy, but died at the age of 7 months. She miscarried several times before a healthy girl, who will become Queen Mary, but never bore a son.
Henry was angry with Catherine, for not bearing a son, and wanted to divorce her, but Pope Clement VII did not allow this divorce. So Henry ignored the Pope, banished Catherine from his Court, and married Anne Boleyn.
In 1534, Henry declared himself as the head of the church of England, via Royal Supremacy, this is called the Act of Supremacy. He separated himself from Rome, just because the Pope did not grant his divorce.
But Anne Boleyn, just like Catherine, couldn't bear him a son and Henry saw this as a betrayal and executed Anne in 1536, but she did bear him another daughter, Elizabeth.
Next he married Jane Seymour 10 days later, and Jane finally bore him a son, Edward, in 1537, who will become the next king. However, Jane died later that year from difficulties in birth.
Henry married 3 other woman after Jane. His last wife helped Henry reunite with is daughters, Mary and Elizabeth, to be the next successors after Edward.
Henry became quite obese and couldn't even walk around without the help of mechanical machines, and had several wounds from a jousting incident. He died at the age of 55 in 1547, and was succeeded by his son Edward IV.