In 1520 a girl was born to Sir William and Lady Askew, and given the name of Anne. Sir William was a gentleman with extensive estates in Lincolnshire and Nottinghamshire. In that year, one of the big stories of the day was what was happening in Germany, where a monk by the name of Martin Luther had challenged the power claimed by the pope to exercise power over Christians in this world and the next. He taught that people were saved by faith in Christ who was the only mediator between man and God and swept aside Catholic paraphernalia of confession, penance, pilgrimages and the veneration of relics.

When, in January 1521, the pope declared Luther a heretic and excommunicated him most people thought he would be burned to death. But thousands of people all over Europe believed the simple Bible message of salvation by faith and the Reformation gathered pace.

In the years that Anne was growing up even a girl living in rural obscurity could not be unaware of the changes that were sweeping through the land. Henry VIII fell out with the pope, who refused to annul the king's marriage to his first wife, and declared that he himself was head of the English church. He followed this by closing all the monasteries. Many of his subjects were enraged at the king's 'heretical' activities. In 1536 there was a mass rising in Lincolnshire during which Anne's father was captured by rebels and his house occupied by defenders of the old Catholic faith. It must have been a terrifying experience for the teenager and her family.

But something even more profound was transforming her life: she was studying the Bible. In 1536 copies of William Tyndale's English New Testament were being smuggled into England from Germany and the Netherlands. The book was banned and the authorities made bonfires of confiscated copies. But that did not deter the adolescent and precocious Anne. She acquired a copy, read it, re-read it and re-read it again and again. It totally changed her life.

Anne, I think, must have been a troublesome teenager – impulsive, self-willed, independent-minded and argumentative. That may have been why her father was keen to have her off his hands. He arranged a marriage for her with Thomas Kyme, a landowner from deep in the Lincolnshire fens, whose family had been involved in the recent rising. It was never going to be a happy marriage because husband and wife were at odds over religion. Anne considered that her domestic duties included reading the Bible to her servants. She went further. By this time (1539) the king had been persuaded to sanction an official, English 'Great Bible' and have it set up in every church. Anne started reading it there and explaining it to any neighbours who cared to listen. This scandalised the local clergy and, spurred on by them, Thomas tried to stop her activities.

Faced with the dilemma of whether to obey her husband or her God, Anne sought a divorce, claiming that this was sanctioned by 1 Corinthians 7:12-16. The couple split up and Anne eventually made her way to London, where she had relatives and friends who shared her faith. She soon gained a reputation as the 'Fair Gospeller', ever eager to seek others.

But the capital was a dangerous place to be. Catholic activists were eager to weed out 'heretics' and have them condemned. Anne was arrested a couple of times and examined by the Lord Mayor and the Bishop of London. She wrote accounts of her interrogations and had them smuggled out of prison to her friends. Her opponents tried badgering her and tricking her into confessing unorthodox opinions. But Anne gave as good as she got. 'What sort of an answer was that?' one frustrated inquisitor demanded. 'A poor one,' Anne replied, 'but good enough for the question.' Over and again she scored with such pert responses and with accurate quotes from Scripture. Eventually she was released and returned to her brother's home in Lincolnshire. But her troubles were not over.

Desperate to halt the Reformation, Catholic activists were attacking evangelicals at the royal court, including Queen Catherine Parr. Because Anne had court connections she was brought back under armed guard and examined in the Tower of London. There her tormentors added torture to mental bullying, only stopping when Anne had lost the use of her legs as a result of being racked. Despite the pain she refused to give her interrogators the names they were looking for.

Anne Askew was condemned as a heretic and burned at the stake in Smithfield, London, in July 1546. Her silence protected some of the most influential evangelicals who were able to continue the work of Reformation. Her fearless proclamation of her faith – both spoken and written (soon published and widely distributed) led to the conversion of many.

Derek Wilson is one of Britain's leading authors of history and historical fiction. In a writing career spanning half a century he has written more than 70 books. This article is based on his most recent, 'The Queen and the Heretic – How two women changed the religion of England', published this Friday (April 20) by Lion Hudson.