Search for the fourth-century Egyptian philosopher Hypatia on the internet, and among other images will be several of a woman painted in the third quarter of the second century AD. The painting is a face mask, placed over the mummified remains of a dead person, a traditional Egyptian custom reinterpreted for the Graeco-Roman style of the Roman Empire. It was also about two hundred years old when Hypatia was born. The internet generation rediscovered Hypatia as a woman of science and ancient precedent for today’s women mathematicians, engineers and physicists, but it needed an image to act as Hypatia’s standard. This portrait has caught on and is linked with Hypatia on many websites. Hypatia is the guest lead of Simon Guerrier’s Companion Chronicle The Library of Alexandria, and Ian Chesterton’s description of Hypatia (as written by Simon Guerrier) as having 'black wavy hair... cut very short' is reminiscent of that appropriated portrait.

The connection is relevant because The Library of Alexandria is in part about memes – ideas which reproduce themselves through and across cultures as genes do in biology, mutating as they try to adapt to new circumstances. In the manner of the early television stories set in the human past, the TARDIS travellers are visiting a specific event in Earth’s history, the destruction of the Library of Alexandria. As Susan states early in the story, we don’t actually know when and how the Library was destroyed. There are reports that the Library was destroyed by Julius Caesar in 48BC, by the Roman Emperor Aurelian around 274AD, on the orders of Theophilus, bishop of Alexandria, in 391AD, or by the Arab commander Amr in 642AD. Every incident was part of a major change in the government and culture of Egypt. Connections with the destruction of the Library weren’t necessarily made at the time of each incident. According to James Hannam at bede.org.uk, Hypatia, represented as the last proponent of the pre-Christian Greek intellectual tradition, has only been associated with the destruction of the Library since Carl Sagan linked her to its supposed destruction in 391 in his television series and book Cosmos (1980). Susan tells Barbara and Ian that memes are after their time, as they are, the word having been coined by Richard Dawkins in the 1970s; the adaptation of the tale of the destruction of the Library to include Hypatia is after their time too, and its inclusion at the heart of The Library of Alexandria suggests it’s a successful meme within a thirty-three year timescale.

The Library of Alexandria offers the devices of the first season historical stories interpreted within the legacy of the intervening five decades. The post-2005 series with its emphasis on interpersonal relationships is an influence, with Ian having to deny to his companions (especially Barbara) that he has been on a ‘date’ with Hypatia. Likewise Hypatia’s lecturing style and complaints about library departments not talking to one another are rooted in the twentieth and twenty-first centuries rather than the fourth and resemble the presentation of Shakespeare as a media celebrity in The Shakespeare Code. The compression of several allied institutions, such as the reading rooms of the Museion (place of the Muses) into the Library for narrative purposes is a useful shorthand and one with a long pedigree. The anachronistic elements help highlight the differences, though: the descriptions of the tagged books on handwritten scrolls, for example. Hypatia’s first quayside meeting with Ian and her desire to seize the cargo of a book-smuggling vessel humorously conveys the very real ruthlessness of the Library’s acquisitions policy. We even get a short lecture on papyrus manufacture and how many words could be accommodated on a single scroll, which would no doubt warm the heart of Sydney Newman were he still with us. Likewise Newman would probably have liked the direct relation of the Library to twentieth-century research centres and the 1960s space programmes.

Less likely to have won Newman’s admiration are Mim, the monsters of this piece. Like meme the word Mim is derived from mimeme, an imitated thing, and these spacefaring creatures are size-varying, form-changing symbols of the evolution of ideas. Their bodies read situations, can become human-shaped, aquatic or airborne, and unsurprisingly are described in terms drawn from the mythology of the Eastern Mediterranean. It’s a credit to all concerned in writing, directing, performance and sound design that they can be easily visualised in all their many shapes. Toby Hrycek-Robinson’s compositions sound as if they could have been played by the historical instruments Ian finds in the Library’s collection and the music suite is a welcome extra.

Director Lisa Bowerman has recruited another former regular from the early years of Casualty, Susan Franklyn, as Hypatia. Franklyn turns in a confident, flirtatious performance which easily engages both listener and principal narrator. William Russell again shows he can reinhabit the voice and personality of Ian Chesterton, as authoritative over customs men in Roman Egypt as he was over pacifist Thals or petty Arab criminals. He also recovers a lot of the tics of Carole Ann Ford’s Susan, but the Doctor very much draws on the octogenarian Russell’s own experience, fitting as this is a first Doctor viewed through the lens of 2013 as much as that of 1964.

For all the musings on memes, it’s the written word which the characters treasure. Barbara risks her life to save manuscripts from fire and the final scene takes place around one of the most celebrated inscriptions in the history of the rediscovery of ancient Egypt by the modern west. As the final scene suggests, more of the Library survives than just its idea, fragments of its collections surviving in other places to this day; the knowledge held and disseminated from there underpins the 1960s life of Ian and Barbara, and the realities and fictions of Doctor Who.