Just to clarify: when you say "version" I'm going to assume you're referring to a performance rather than a text.

What we know about performances from Early Modern London is that they were required to be approved by the Master of Revels before performance. The Master of Revels was a court position underneath the Lord Chamberlain and records were kept for petitions of plays and plays that were approved or rejected. The Master of Revels during Shakespeare's life was Edmund Tilney. In most cases there isn't much information in the record except the title of the play, a date, and sometimes a playwright's name. But, if we know the date and the playwright or the theatre then its possible to put together an idea of the people who performed it because we know the names of those in the most popular theatre companies at the time. It's why we can confidently say that Richard Burbage played Hamlet and that Edward Alleyn probably played the title role in Marlowe's Faustus, as examples.

But, when it comes to Julius Caesar, the first and earliest record we have is when the First Folio was entered into the Stationer's Register on Nov. 8, 1623. But that's the text of the play, not the performance (the Stationer's Register is for records of licenses granted to printed materials). So, unfortunately, it's impossible to know if, when, where, and who performed the first or 'authoritative' Julius Caesar.

But Bart van Es in Shakespeare in Company discusses the acting company and relationships to Shakespeare. He also includes a date of 1599 for the first performance of Julius Caesar in his appendix. But he provides some excellent historical insight into the London theatre scene and its major actors, including Burbage. Because Burbage was THE leading actor of The Lord Chamberlain's Men the safe assumption as to who played Caesar was Burbage. And if van Es is correct that the play first went up in 1599, then it would have happened in the first season at the Globe. So there is some information that we can piece together.

My major source for this was Janet Clare, "'Greater Themes for Insurrection's Arguing': Political Censorship of the Elizabethan and Jacobean Stage" from The Review of English Studies (May 1987).

EDIT: Added the Bart van Es information.

Just to clarify: when you say "version" I'm going to assume you're referring to a performance rather than a text.

What we know about performances from Early Modern London is that they were required to be approved by the Master of Revels before performance. The Master of Revels was a court position underneath the Lord Chamberlain and records were kept for petitions of plays and plays that were approved or rejected. The Master of Revels during Shakespeare's life was Edmund Tilney. In most cases there isn't much information in the record except the title of the play, a date, and sometimes a playwright's name. But, if we know the date and the playwright or the theatre then its possible to put together an idea of the people who performed it because we know the names of those in the most popular theatre companies at the time. It's why we can confidently say that Richard Burbage played Hamlet and that Edward Alleyn probably played the title role in Marlowe's Faustus, as examples.

But, when it comes to Julius Caesar, the first and earliest record we have is when the First Folio was entered into the Stationer's Register on Nov. 8, 1623. But that's the text of the play, not the performance (the Stationer's Register is for records of licenses granted to printed materials). So, unfortunately, it's impossible to know if, when, where, and who performed the first or 'authoritative' Julius Caesar.

But Bart van Es in Shakespeare in Company discusses the acting company and relationships to Shakespeare. He also includes a date of 1599 for the first performance of Julius Caesar in his appendix. But he provides some excellent historical insight into the London theatre scene and its major actors, including Burbage. Because Burbage was THE leading actor of The Lord Chamberlain's Men the safe assumption as to who played Caesar was Burbage. And if van Es is correct that the play first went up in 1599, then it would have happened in the first season at the Globe. So there is some information that we can piece together.

My major source for this was Janet Clare, "'Greater Themes for Insurrection's Arguing': Political Censorship of the Elizabethan and Jacobean Stage" from The Review of English Studies (May 1987).

EDIT: Added the Bart van Es information.