He lived in the turbulent 17th century of English history which saw the execution of Charles I (1600-1649) for treason after he had been defeated in a civil war with the 'Model Army' (Parliamentary army) organised by Oliver Cromwell.
Bunyan, though born of poor parents, was sent to school and learned to read and write which would figure so prominently in his future. He served as a soldier on the Parliamentary side against the Royalist forces. According to his own words, he cursed, swore, lied, and blasphemed the Lord's name. Yet, he was at the same time troubled by visions of hell-fire.
After his discharge around 1648 he married a poor but godly young woman whose dowry was two explicitly Christian books. The contents of these, along with a certain John Gifford, a pastor of an independent chapel, led to his conversion to Christ after a long* struggle.
With his conversion, he began to preach (unlicenced) which was allowed in the 'Commonwealth Period', the hiatus between Charles I and his son, Charles II. During the Commonwealth, Oliver Cromwell was the Lord Protector of England, Scotland and Ireland (1649-1658).
However, the monarchy returned after the ineffectual, short administration of Richard Cromwell (Oliver's son). Charles II (1660-1685) enforced the Church of England Prayer Book services on all his subjects; consequently Bunyan was indicted on an old 16thC law regarding failure to attend such services and imprisoned** for six years and then a further six years.
He wrote one of his famous works, Grace Abounding to the Chief of Sinners, an autobiographical work, during his first six years. 
His most famous work, The Pilgrim's Progress (1678), was conceived during his first six-year incarceration and perhaps written during the later imprisonment. A second part describing the journey of Christian's wife, Christiana to the Heavenly City was published in 1684.Finally in 1672, Charles II issued a Declaration of Indulgence which saw Bunyan released from prison and soon after receive a licence to preach as an Independent (so-called because these people were independent of the established Church of England). However, Charles revoked this Indulgence in 1675 and Bunyan went back to prison for a short while.
He was then pardoned, probably through the mediation of the Quakers who were also looking for relief from state persecution. By this time, John Bunyan was famous enough# never to be imprisoned again.
I have written about Bunyan because it is always timely to reflect on those who have gone before us as our spiritual ancestors in the faith of Christ Jesus.
*Bunyan struggled with depression and (what we would call today) an obsessive-compulsive disorder, most notably before he became a Christian. The effects of these conditions made his salvation journey an arduous one.
**He wasn't always kept in close confinement which seemed to relate to the mood of the various gaolers.
#Ironically, the Anglican church accords John Bunyan a 'lesser' feast day to commemorate his work in its yearly calendar!
