The Bard’s life is full of mysteries, but perhaps the greatest riddle of all is what he was doing between 1585 and 1592.

It's strange to think that we still have no idea how Shakespeare "became" Shakespeare. That's because the crucial years between 1585 and 1592, when he went from being an ordinary chap in Stratford to a triumphant actor and writer in London, are a complete blank to us.

As John Nettles, presenter of Shakespeare: The Legacy, puts it, "one minute in 1585 he's in Stratford-upon-Avon... the next moment he's in London, on an upward trajectory towards becoming the greatest poet and playwright the world has ever known."

So what happened during those lost years?

Shakespeare: The Legacy With John Nettles

WAS SHAKESPEARE A CRIMINAL?

One popular story tells us that Shakespeare might have been forced to flee Stratford due to criminal activities. Accounts of the Bard's life from the 18th Century - many years after he died, to be fair - mention that he was apparently a bit of a poacher in his spare time. According to one narrative, Shakespeare was "much given to all unluckiness in stealing venison and rabbits, particularly from Sir ___ Lucy".

This would be a local landowner, Thomas Lucy, who apparently had Shakespeare whipped and fined after the poet was discovered trying to steal deer from his estate. The story goes that, following this disgrace, Shakespeare was essentially exiled from his native land and started a new life in London. But there are no reliable reports from his own time, and historians say there were no deer on Lucy's land at the time.

WAS SHAKESPEARE A SCHOOL TEACHER?

Could the future Bard have spent time as an ordinary schoolmaster during his lost years? It's certainly a popular idea, especially in the Hampshire village of Titchfield, which has claimed that Shakespeare taught in a school there until 1592. Much has been made of the fact that one of Shakespeare's wealthy patrons was the Earl of Southampton, whose land in Titchfield encompassed a school. Add to that the famous account of a 17th Century biographer which states that Shakespeare definitely worked as a schoolmaster, and the Titchfield theory starts to make some sense. But this is still hearsay with no solid evidence to back it up, especially considering Shakespeare wasn't university educated and rather unqualified to be a school master.

DID SHAKESPEARE BENEFIT FROM A MURDER?

At the exact time of the lost years, a travelling group of actors known as the "Queen's Men" made their way from town to town, entertaining locals with plays, acrobatics and variety acts. What has this got to do with Shakespeare? Well, we know that during one stop-off, a member of the Queen's Men called William Knell got into a brawl with a fellow actor, and ended up dead with a blade in the neck.

The theory goes that the group, now down by one man, moved onto Stratford where a certain budding young actor called William Shakespeare was - as John Nettles says - "taken on board to replace the William Knell who'd been murdered, and the company took him with them on the rest of the tour and then back to London". A deliciously scandal-laden theory, certainly, but did it really happen that way?

WAS SHAKESPEARE A SOLDIER?

Here's yet another theory: that Shakespeare actually served as a soldier or sailor during the lost years. This was an era when Protestant England was under threat from Catholic forces, and when the Spanish Armada was launched on its doomed attempt to take the nation. Men were enlisted to defend these shores, so might Shakespeare have been one of them? Some historians point to sections of the plays - particularly the recruitment sequence in Henry IV Part 2 - as "evidence" of his knowledge of the military. Though this could equally have been down to research.

Shakespeare invented the phrases “break the ice”, “fair play”, and “too much of a good thing”... and the name Jessica. — Yesterday TV Channel (@YesterdayTweets) July 10, 2015

DID SHAKESPEARE GO TO ITALY?

One of the most controversial theories about Shakespeare is that he was a secret Catholic. That would have put him in a very dangerous position in Elizabethan England, but could he have made a religious pilgrimage to Rome itself? As ever, the evidence is far from solid, although there is a 16th Century guestbook in Rome which some believe shows three separate signatures by Shakespeare. And so many of Shakespeare's plays, from The Merchant of Venice to Romeo and Juliet, have Italian settings, which may be a sign he knew the culture first-hand. Or maybe not.

What do you think? Watch John Nettles talk us through the major theories, and add your own below...