That seems intentional: at different times in the story, the Doctor's companion Ian quotes dialogue from Shakespeare's plays King Lear and The Merchant of Venice, while among the famous stories that another companion, Barbara, intends to share with Saladin is Romeo and Juliet.

Shakespeare who lived 400 years after Richard the Lionheart didn't write a play about Richard, so why would the makers of Doctor Who want to link Richard to Shakespeare?

It might help to compare The Crusade to An Age of Kings, a highly ambitious BBC series from 1960 that adapted eight of Shakespeare's plays to tell, in fifteen feature-length instalments, the story of successive English Kings, starting with Richard II and ending with Richard III. As the British Film Inst.i.tute has said, it was 'effectively presenting a chronological history of British royalty from 1377 to 1485'.

The Crusade has something of the look and feel of An Age of Kings not least because Richard the Lionheart is played by Julian Glover, who also appeared in An Age of Kings in several prominent roles, including as Edward IV. Perhaps the makers of The Crusade weren't consciously aping that particular production, but the fact that they made Richard sound Shakespearean tells us something about their depiction of history. The Crusade is, consciously or not, part of a fashion in television drama in the 1960s.

Shakespeare's version of history was often inaccurate and, in some cases, wholly untrue. Yet his skills as a dramatist are highly respected something we can tell was true in the early 1960s by that fact that An Age of Kings was such a big-budget, prestigious series. By making Richard the Lionheart sound Shakespearean, The Crusade is tapping into the viewers' a.s.sociation of Shakespeare with quality. It's probably not how Richard would really have spoken, yet it makes him seem more authentic.

'The King takes the oath today ... to take the cross as a Crusader. But he did that in London.'

'Who says?'

'Your history books.'

'Perhaps they got that bit wrong.'

'No, no too well doc.u.mented.'

The Fifth Doctor and Tegan Jovanka, The King's Demons (1983)

The King's Demons (1983) is set in the reign of Richard's successor (and brother), King John. The story takes place in 1215, just 24 years after the events of The Crusade but Doctor Who has a completely different look and feel. Most obviously, The King's Demons is in colour and the exterior scenes were recorded on location, in the atmospheric grounds of Bodiam Castle in Suss.e.x. The interior scenes were recorded in a television studio, but they feel very different to those in The Crusade: there is faster cutting between individual shots and use of different angles such as when we look down on the swordfight between the Doctor and Sir Gilles Estram.

These technological innovations and changing fashions in the style of television production help The King's Demons feel less like a televised play than The Crusade. Yet in other ways the historical setting of The King's Demons is less convincing. The iron maiden torture device that is central to the plot is completely out of place: the earliest known reference to such an instrument is from 1793. Perhaps, since the iron maiden turns out to be the Master's TARDIS, it's him who has got the history wrong.

Other things are less easy to explain away. The hair and clothes of the thirteenth-century people all seem much too clean, especially in the brightly lit interior scenes. Bodiam Castle might look atmospheric but its square shape, with a central courtyard enclosed by structures built into the surrounding curtain wall, are typical of when it was built which was in 1385, more than 150 years after The King's Demons is set. To the people of 1215, a castle like the one shown in Doctor Who would have seemed futuristic!

What's more, although an appropriate castle, costumes and props can make a medieval setting seem authentic at least to a non-expert eye it's much more difficult to get the plants and trees just right. Many species now common to the UK were only introduced in the last 300 years and we often know exactly when particular plants first arrived. Disease, such as the outbreak of Dutch Elm Disease in the 1960s, can also drastically change the make-up of plant life in the countryside so that it's even less likely that what we see in a TV story set in the past will be accurate.

It might be ironic for a story about the Doctor's efforts to ensure that history is not altered, but The King's Demons isn't aiming for a perfect recreation of the year 1215. Rather, it's conjuring a myth, one based on a popular, twentieth-century idea of the Middle Ages instead of the historical evidence.

Something similar is happening in Robot of Sherwood, but here the distinction between the popular, modern idea of history and what the period was really like is the whole point of the story. As the Doctor says, the real 1190 should have 'No damsels in distress, no pretty castles, no such thing as Robin Hood.' Like the Doctor, we don't expect Robin Hood to be real or at least to be anything like the heroic character we've seen in the movies.

It's striking how very different The Crusade, The King's Demons and Robot of Sherwood all look, despite showing the same character (the Doctor) in the same kind of adventure story full of action and ingenuity, and set in roughly the same period of history. The fact that over time the telling of this same kind of story becomes faster paced and more complicated is not just the result of developments in the technology used to make television: it's because we as the audience have kept up with those innovations. We can follow faster, more complex stories in fact, we demand them from the people who make TV. Watching old Doctor Who stories and finding them stilted or slow is a sign of how much we take developments in technology for granted in our daily lives.

Watching old Doctor Who can reveal to us changes in lots of things we take for granted, the 'norms' or informal, unspoken ways we understand that we should all behave. Doctor Who is made for a broad, family audience. It might sometimes push the boundaries, but the people making the series always have that broad audience in mind. They might edit a scene to make it less violent or, as in the case of Bad Wolf (2005), to remove a glimpse of Captain Jack's bare bottom which was not considered suitable for the audience.

What is deemed suitable for a family audience can also change over time. Shortly before the transmission of Robot of Sherwood, a real-life incident prompted the people in charge of the programme to remove part of a scene in which a character was beheaded. As recorded, Robin lops off the head of the Sheriff of Nottingham in their duel but, since the Sheriff is a robot, he picks his head up and puts it back on before continuing with the fight. That joke didn't seem so funny in the context of real events at the time of broadcast.

Other changes in what is considered suitable happen more gradually but we can spot them by comparing old and new Doctor Who. In this way, the series can act as a historical doc.u.ment, giving us evidence of sociological developments over time.

For example, in The Parting of the Ways (2005), as Captain Jack prepares to battle the Daleks and knowing he's likely to die he kisses Rose Tyler and then kisses the Doctor. This onscreen kiss between two men caused a moderate stir in the media, as did the fact that the character of Captain Jack was openly bis.e.xual. Some argued that such things weren't suitable in a TV show intended for a broad, family audience. Others disagreed as clearly did the makers of Doctor Who, since they put it in the programme. Gay and bis.e.xual characters have continued to appear in the series ever since.

But a kiss like that could never have happened in Doctor Who when it began in 1963 not least because h.o.m.os.e.xuality was against the law in the United Kingdom until 1967. By the same token, in Doctor Who of the 1960s there are plenty of things that were taken for granted as being suitable for a family audience or at least relatively uncontentious that would never make it into the modern programme. In the very first episode, An Unearthly Child (1963), the Doctor refers to a 'Red Indian' with a 'savage mind' language that is now considered culturally insensitive and very unlikely to be used in the series today.

If, like the Doctor, we could travel back in time to see those old stories when they were first broadcast, plenty of other things would make us realise how much the world has changed over time. For one thing, we would notice the smell.

'The West Country Children's Home. Gloucester.

By the ozone level and the drains, mid-90s.'

The Twelfth Doctor, Listen (2014)

In Chapter 8, we talked about the relationship between time, memory and our sense of smell. If we could travel in time, our sense of smell would perhaps give us a vivid sense of scientific and technological change. Journeying back into Earth's history, we might, as the Doctor does in Listen, use our sense of smell to tell the time period we'd arrived in.

For example, on 1 July 2007 the day after the broadcast of The Last of the Time Lords a law made it illegal to smoke in enclosed work places in England. Similar laws had recently been pa.s.sed in Scotland, Wales and Northern Ireland, too the result of ever more scientific evidence that smoking increases the likelihood of a number of fatal diseases, not only for the smoker but for those breathing in secondhand smoke.

The smoking ban is still recent history. Yet, if we could journey back less than a decade to a time before the ban, we'd be struck by the smell of smoke in public buildings. Cigarette smoke lingers, so we'd notice the smell even if no one was actually smoking there.

In fact, we can be struck by the smell of cigarettes in public places without having to travel in time; we just need to visit countries that don't have the same ban. But then, as it famously says in the opening line of L.P. Hartley's 1953 novel, The Go-Between, 'The past is a foreign country: they do things different there.'

The further back we went into history, the more we'd notice strange sights and sounds and smells and the more 'alien' the world would become. Just as in Chapter 7 we could use the stars to deduce our position on the surface of the Earth, we could calculate when in history we were from tell-tale clues around us. For example, in the United Kingdom: Before 2000 Relatively few people had mobile phones before 2000. Before that, mobile phones were chunky and the further back in time we go only owned by the richest people. We'd also notice more people hanging around apparently not doing anything. We'd find that suspicious if we saw it today, but before mobile phones, there was no way to know if friends you were meeting were running late, so you just had to wait.

Before 1980 The end date isn't exact, but we might notice more men scarred and otherwise showing signs of service in war. We still see some wounded veterans today, mainly from recent conflicts, but we'd see many more in the past because of conscription in the First and Second World Wars, which meant so many more men went to fight.

Before 1965 Few people had automatic washing machines in their homes until the mid-1960s. There were other kinds of washing machine before that, but for many people clothes were washed by hand generally less often and less thoroughly. Many homes still had only basic washing facilities rather than fitted bathrooms. So we'd notice that people were smellier. And fluoride toothpaste which is especially good at stopping cavities in teeth was first sold in 1956 but only became popular in the mid-1960s. Before then, too, we'd notice people's terrible teeth.

Before 1948 Prior to the beginning of the National Health Service, we would see more sick and injured people who hadn't been treated. We'd notice poor-sighted people struggling without gla.s.ses, and people with few or no teeth who had not been given dentures.

Travel further back to when horses were a more common form of transport than the car and we'd notice another change in smell. Animals would live much closer to humans, and there would be horse dung all over the roads. We might notice there was less pollution and overcrowding, and much more green s.p.a.ce. Or we might notice how much dirtier, bleaker and unhealthy everything looked, with fewer laws (and understanding) about even basic health and safety.

'I don't know how to tell you this, oh great genius but your breath doesn't half stink!'

Martha Jones to William Shakespeare, The Shakespeare Code (2007)

But perhaps the most striking thing we'd notice if we could really travel back in time and which comes over clearly from nearly all the historical evidence we have is that people wouldn't change much. We would see the same human behaviour, the fears and desires, the foolishness, meanness and kindness. One reason the plays of Shakespeare remain so popular after 400 years is that the psychology of his characters rings as true to us now as it did when he wrote them.

The difference between people in history and you and me today is the context in which they lived and understood the world around them. They'd send letters not text messages to tell someone they fancied them (in the past there were more frequent postal services, so you could get a reply the same day). They'd travel by horse-drawn carriage instead of a car. They'd die young of diseases that we can cure easily. Generally, their lives would seem harder and shorter because of the advances made since their time.

We might even argue that what we see in history is the effect on human existence of developments in knowledge and technology. Which would mean, whether or not history is a science, in some ways it is the study of how science has changed humanity.

The Doctor pushed through the last of the undergrowth and stepped out into what amounted to a forest clearing. His long white hair was swept back, but his eyes had the sharpness of a man half his apparent age. He leant on his cane, mopping his forehead and studying the edifice that loomed over him. 'I knew it,' he muttered with a degree of satisfaction. 'Susan, I was right! It's not a building at all.'

Susan almost fell into the clearing. The long gra.s.s had somehow wound round her ankle and she had to struggle not to lose one shoe altogether. She wore the patterned top she had won at the cloud fair on the mountainous planet Orrios. It wasn't remotely practical for exploring an alien rain forest, but she liked it and was not going to change just because her Grandfather had registered his disapproval. She sat on the ground to adjust her shoe and squinted up at the object that towered above her.

'It's a s.p.a.ceship, isn't it?' she said.

A dark green wave of vegetation had broken over the grounded craft. Vines traced across its hull like veins. Heavy roots like knotted fingers gripped the fuselage, trying to crush their way inside. A small tree hung with scarlet flowers had rooted in one of the engine vents.

Nothing moved. No breeze stirred the leaves, no birds sang. Only the occasional splat of water dripping from the upper canopy broke the silence.

'Obviously some expedition has come to grief here,' the Doctor declared. 'Judging from the repair work on the hull, it was an old ship, but as to what caused its demise, I have no idea.'

While he paced off around the ship's hydraulic legs, looking in vain for an entrance, Susan walked to where a line of gra.s.sy tussocks bordered the edge of the clearing. New saplings, already young trees in their own right, were taking advantage of the extra sunlight where their ancient forest forebears had been cleared. It was hot in the open, so she sat down on one of the tussocks.

The air fizzed for a moment and the row of tussocks was suddenly alive. Susan stumbled back up to her feet as a silvery face flickered through the long gra.s.s on every mound. Women and men; some smiling gently, some broadly. A couple frowned. One winked. Another (very serious) raised her hand in military salute. Another was laughing as he carried a silently barking dog.

Susan felt uncomfortable as if she had just disturbed something sacred. And then the Doctor was at her side, surveying the display with a look of grave reverence. 'Well, this answers our question. Apparently most of the people on the expedition died.'

They walked arm in arm along the row reading the little commemorative name tags that had appeared below the faces. Flight Lt. Franois Degrey, Captain Cornelia Parsotam, Snr Orderly Andy Bryant and Pooch. It wasn't menacing, just a little sad. And it occurred to Susan that one of the crew, the last one alive, wouldn't be able to bury himself.

The line of tussocks ended with one new grave, freshly dug, which had no holographic memorial. Out of the mound of bare earth sprouted a spherical grey s.p.a.ce helmet with a metal name tag attached. It named the owner as Captain Tino Driscoll KST.

'But this is only a few days old,' said Susan. 'So there must be survivors.'

The Doctor frowned. 'Except that the other graves have been neglected for many years. That's quite a disparity, don't you think?'

A sudden wind rustled through the trees above, scattering flowers down upon them.

Susan shuddered. 'Can we go now, please? This place gives me the creeps.' She took his arm again and tried steering him back towards the path leading to the TARDIS. To her frustration, he stopped, studied the abandoned s.p.a.ceship and then glanced back at the graves.

'There are twenty-three colonists buried there, yet how many people do you think that ship was built to carry? I'd say quite a few, eh? At least one hundred.'

'Well, then they must have survived. Perhaps they found a better place to set up home.' She tugged at his arm, but he pulled free.

'But that doesn't explain the new grave.'

'Oh, Grandfather,' she complained.

He pointed upwards at something catching the sunlight: a one-eyed metal insect that winked as it flew down towards them. Susan tried again to pull him away, but the Doctor stood his ground, determined to match the prying object's stare. It stopped, humming slightly, hovering a couple of feet above them. 'Can I help you?' he called and Susan saw his knuckles whiten as he gripped his cane.

The undergrowth nearby opened with a crash and a figure in a bulky grey s.p.a.cesuit stumbled into view. It stopped short when it saw them and swore loudly in a woman's voice. Then it strode in their direction with ungainly steps. 'Are you crazy? Who the heck sent you?' The dark shading on her visor cleared. She was young with sandy hair drawn back tight. Her eyes were sharp with suspicion. 'You'll get yourselves killed without a suit!'

Susan gripped the Doctor's hand, but he seemed unconcerned. 'Young lady, I have no idea what you are talking about.'

'It's the zeitgeist thing again, isn't it? Who are you with? Avbigo? Or Tyzor Properties? Once one developer gets the smell of a possible killing, then you all pile in.'

'Is this your flying camera?' said the Doctor. 'Would you please call it off?'

She studied them for a moment. 'Jeeps, you two take the m.u.f.fin. That's the trouble with the open market. These days, any old codger can set up a claim.'