Two historians today (16JAN07) launched an appeal to overturn a ruling that author Dan Brown didn't plagiarise their work for his bestseller The Da Vinci Code. Michael Baigent and Richard Leigh were both at the hearing in London's High Court. They claim Brown copied their book The Holy Blood And The Holy Grail. However, a judge ruled last April (06) that the themes in their work are too general to be protected by copyright. Brown made an appearance in court during the original hearing, but is not expected to do so for the appeal. Last year, he argued that authors must be allowed to reference historical sources without fear of a lawsuit. The appeal is expected to finish by Friday (19JAN07) with a decision following in writing.