LINDY Hume's first Sydney Festival must surely put an end to tired old arguments about whether you're allowed to muck around with the classics.

First, because the festival has included several superb productions that did just that; and second, because none of these productions, for all their innovation and for all the changes they made, and the new twists they introduced, have seemed in the least bit disrespectful.

It has been a festival in which interesting new versions of great works have been allowed to talk to each other and in which audiences have been encouraged to reflect on why and, more important, how some works can survive social and political change while others fail to do so.

Ever since "classics" were invented, artists have reworked them. Sophocles rewrote Homer (already a classic in 5th century BC Athens) and was in his turn rewritten by Ovid, who was plundered by Shakespeare, who was performed for hundreds of years in rewritten versions.

Nahum Tate's happy-ending adaptation of King Lear is the version that was played for most of the play's stage history.

Pirandello's early modernist classic Six Characters in Search of an Author even nods to Hamlet in the story of the mysterious characters who take over the stage and challenge our understanding of what is real. In Britain's Headlong Theatre's version, one of the theatre highlights of the festival, it wasn't a stage they took over but a modern film studio.

The reality that was being challenged was the now conventional dramatised documentary. This superficially radical alteration of the play enabled the adaptors, Rupert Gould and Ben Power, to reimagine for a contemporary audience a work that had lost a lot of its power.

But let's go back to Sophocles, whose Oedipus is the classic text of a story that is so well known, 2500 years after Sophocles's version was written, that its title has an adjectival form.

There were two adaptations in this festival: Ireland's Pan Pan Theatre's Oedipus Loves You, a version (in this case irreverent) that attempted (in this case unsuccessfully) to link comically the original myth with a pop interpretation of the modern Freudian version; and, much more excitingly, Peter Sellars's production of Stravinsky's opera-oratorio Oedipus Rex.

Sellars's fine production, having told the story in the first half using Cocteau's Latin text but with Antigone as the narrator doing chorus speeches from the Sophocles original, managed in the second half to pursue the blinded Oedipus to his death, as Sophocles did in Oedipus at Colonus.

After the interval, Ismene and Antigone grieved over Oesipus's grave as the Sydney Philharmonia Choirs, ranged around the orchestra and spread throughout the Sydney Opera House Concert Hall, sang the beautiful music of Stravinsky's Symphony of Psalms.

As in the Greek original it showed a chorus of ordinary citizens singing their baffled community response to the almost incomprehensible tragedy of the mythic protagonists. The effect was astonishing and moving.

Then there's the greatest Oedipal play of all, Hamlet.

At last Schaubuhne Berlin came to Sydney, in a production by Thomas Ostermeier, who has had an influence on some of the best Australian theatre directors. This was another example of an apparently radical version of a classic that was nevertheless deeply respectful of its source.

Lars Eidinger's performance, as a shambles of a prince whose comic madness undermines not only the Danish court but the theatre we are in - with cheerful ad lib asides mocking the classic conventions of Shakespearean soliloquies - still gave us the troubled Hamlet of the tradition. It's just that he was also crazy and funny, a sort of South Park Hamlet, and therefore, for a contemporary audience, all the more tragic when everything comes unstuck.

The only soliloquy that was left out of the Schaubuhne Hamlet, "Oh what a rogue and peasant slave am I", suddenly popped up in Six Characters, along with a number of references to the festival, including a scene in which director Rupert Gould complained that the Schaubuhne had received more funding than Headlong.

This sort of playfulness is a feature of Hume's festival, which brings together a good number of absorbing shows and lets them interact. It has kept Fergus Linehan's grand celebratory First Night Party, taking over the city and opening its streets to large crowds of people who might not go to anything else, but keeping them alert and moving with a range of street performances between venues. It introduced, in Rogue's Gallery, a performance in the Opera House forecourt of sea songs and pirate ballads by performers such as Sarah Blasko, Marianne Faithful and Tim Robbins.

I didn't see this but the negative response it had from many people seems to have stemmed, at least partly, from a feeling that it was disrespectful of the originals.

And then there has been Christopher Alden's superbly brutal new Tosca for Opera Australia - not part of the festival, but another adaptation that has caused controversy. Perhaps opera audiences are particularly sensitive about their classics but as a theatregoer I couldn't see what the fuss was about. It is thrillingly urgent and immediate.

Starkly political, set in Berlusconi's Italy, in a drab vestry lined with Forza Italia posters (and with the sacristan in his little glass office watching one of Berlusconi's TV channels), it brings Puccini's work into the 21st century with extraordinary power.

It has a wonderful Tosca (Takesha Meshe Kizart, in January) so deluded that she only imagines her final meeting with her lover Cavaradossi, and so feisty that, rather than throwing herself romantically off a balcony, she has to be shot, like Carmen in Hume's controversial 1995 production of that other great tradition-bound opera.

All the supposedly radical adaptations in the theatre this January have really just been reinvigorations of originals that were alive at the time they first appeared but have now died and become entombed in the sediment of theatrical and operatic convention. This might be a definition of a classic - a work that has become a fossil.

Doing the classics in the way they were first done, or in the way in which subsequent staging traditions have fixed them, simply takes the fossils and places them carefully, perhaps lovingly, in a museum. Neither Hume's festival nor OA's new Tosca have been particularly subversive (come back, Barrie Kosky!) but at least they haven't given us museum pieces. What these respectful but reinvented productions of Oedipus, Hamlet, Six Characters and Tosca have done is to make old classics alive again, fit to walk the mean streets of the 21st century.