William Tyndale's translation of the Bible.
Tyndale (c. 1494 – 1536) was a 16th-century Protestant reformer and scholar who, influenced by the work of Desiderius Erasmus and Martin Luther, translated the Bible into the Early Modern English of his day. Tyndale’s was the first English translation to draw directly from Hebrew and Greek texts, and the first to take advantage of the new medium of print, which allowed for its wide distribution. In 1535, Tyndale was arrested on the orders of King Henry VIII, jailed for over a year, tried for heresy and strangled before his body was burnt at the stake.
Tyndale's final words, spoken were reported as 'Lord! Open the King of England's eyes.'
Much of Tyndale's work eventually found its way into the King James Version (or 'Authorised Version') of the Bible which drew significantly on Tyndale’s translations.
Some of the new words and phrases introduced by Tyndale did not sit well with the hierarchy of the Roman Catholic Church, using words like 'Overseer' rather than 'Bishop' and 'Elder' rather than 'Priest', and (very controversially), 'congregation' rather than 'Church' and 'love' rather than 'charity'. Tyndale contended (citing Erasmus) that the Greek New Testament did not support the traditional Roman Catholic readings.
It's also interesting to see how the spelling and grammar in English has changed since Tyndale's day.
e.g. Here's Genesis 1:1-4:
'1 In the begynnynge God created heaven and erth.
2 The erth was voyde and emptie ad darcknesse was vpon the depe and the spirite of god moved vpon the water
3 Than God sayd: let there be lyghte and there was lyghte.
4 And God sawe the lyghte that it was good: and devyded the lyghte from the darcknesse'