Why Was Tyndale Murdered?
When Tyndale published his English translation of the Bible in 1526, he put himself at extreme risk. "He did this in an era when the English Catholic church had in effect a law that made it a crime punishable by death to translate the Bible into English." If you don't believe that this was a real threat, I need only remind you that in 1519, the Catholic church had murdered a woman and six men for teaching their children English versions of the Lord’s Prayer, the Ten Commandments and the Apostles’ Creed. And that Tyndale (at age 42) was strangled and then burned at the stake for the heresies of translating the Bible into English and questioning the authority of the pope and the established church. The Catholic Church was so set upon ensuring that Tyndale's translation was destroyed that on two separate occasions, they bought as many copies of the translation as they could and then set them on fire. Yes, book burning was a thing even in England.
Why would Tyndale embark on such a dangerous effort? He highlights this in The Obedience of a Christian Man
(available at Amazon @ https://www.amazon.com/Obedience-Christian-Man-Penguin-Classics/dp/0140434771/ref=sr_1_1?s=books&ie=UTF8&qid=1467906002&sr=1-1&keywords=the+obedience+of+a+christian+man
). You can also download the book in PDF form from a variety of online sources. And I would point you to two articles about the book: one a fantastic summary of Tyndale's polemic (http://www.christianitytoday.com/history/issues/issue-16/from-archives-from-obedience-of-christian-man.html
) and the other an article about the polemics between Tyndale and More (https://www.christianhistoryinstitute.org/magazine/article/pen-and-ink-wars-or-tyndale-vs-more/
If you want to read why the man felt honor bound to translate the Bible into the vernacular, then I urge you to read his treatise about the necessity of vernacular translations. Only then should we discuss whether translating the Bible into the vernacular is heretical.