Let's start by considering the fact that one third of history is missing: because people were asleep. Today it's rude to barge into someone else's bedroom, but this is really relatively new. Until only 100 years ago, people were happy to share not only their bedrooms but even their beds with work colleagues, or even strangers.
Medieval people didn't have special rooms for sleeping, just a single living space for everything. They put up with this lack of privacy partly for the lack of other options. In a great medieval hall like Penshurst Place in Kent, there weren't enough separate rooms for all the servants, so the hall was used as a kind of dormitory with people sleeping on its floor at night. Considering the alternatives, the hall floor was a terrific place to be: safe and warm, even if smoky, smelly and crowded.
Medieval beds were often hay or straw stuffed into a sack ('hitting the hay' had a literal meaning). You just needed a cloak or blanket to cover yourself. These simple medieval beds were designed to be shared. We have instructions dating from 1452 for stuffing a huge sack bed nine feet long and seven feet broad, and etiquette developed about how to take your position in such a communal bed. When the seventeenth-century Abigail Willey didn't feel like having sex with her husband, she made her two children sleep in the middle of the bed, rather than taking their usual position at the sides!
Over time bed linen, sheets, blankets and eiderdowns all developed, reaching a peak of sophistication in the nineteenth century. One Victorian household manual recommends that you sleep in an elaborate set-up consisting of iron bedstead, a thick brown sheet to cover its metal springs, then a horsehair mattress, feather mattress, under blanket, under sheet, bottom sheet, top sheet, three or four blankets, eiderdown, and pillow-covers. It also recommends that you turn the mattresses every morning, and change the pillowcases twice a day (replacing the plain, daytime pillowcases with frilled ones at night).
No one could live like this without servants to help them, and beds became much simpler after the two World Wars destroyed the social system in which domestic service was the largest single source of female employment. But complete liberation from the drudgery of bed-making occurred only in the 1970s, when the duvet or 'continental quilt' was introduced from Scandinavia, by Terence Conran. Duvets were associated with liberation of other kinds: 'sleep with a Swede' was an early advertising slogan in this newly-permissive age. The simplicity of most modern beds - just one mattress, just one covering - takes us back in a strange kind of circle to the medieval.
One particularly intriguing sleeping arrangement was known as 'bundling'. In rural areas, an unmarried young man and women were sometimes allowed by their parents to sleep in a bedroom together. Sometimes they were even tied down, or a board was placed down the middle of their bed. They were supposed to chat all night, just getting to know each other without physical contact. Then they might choose to marry. Bundling was a step along the way towards your spouse being a matter of personal choice rather than someone picked out for you by your parents. It died out because the Victorians found it rather undignified - and in the nineteenth century all the bedroom's social uses fell away and it finally became a private place used just for sleeping.
Next we come to the room in the house that has the shortest history: the bathroom. Two hundred years ago, bathrooms didn't exist. The bathroom's development has not been a straightforward matter, and you might be surprised to learn that many Tudor people had worse personal hygiene than their medieval ancestors.
People often use the word 'medieval' to mean something horrible and dirty, but those at the top of medieval society actually kept their bodies very clean. Medieval London contained numerous communal, mixed-sex bathhouses, with single tubs and communal tubs, steam baths and herbal potions. You could spend the whole day and even have a meal, like a modern spa.
Around 1500, though, bathing entered upon two hundred years - the 'dirty centuries' - of decline and neglect. This was partly because many bathhouses had become brothels, and partly because of fears that water spread illness, especially the new and frightening Tudor affliction of syphilis. People were concerned that polluted bath water might penetrate their skin.
But that's not to say the Tudors and Stuarts had no concept of cleanliness. In their idea about personal hygiene, clean underwear played an important part as it was supposed to soak up sweat. A shirt 'today serves to keep the body clean', wrote a commentator in 1626, more 'effectively than the steam-baths of the ancients who were denied the use and convenience of linen'. Hence the emphasis on sparking collars and cuffs in Tudor portraiture: it signifies a clean body - and a virtuous mind.
The Tudors also overlooked a rather extraordinary invention which didn't catch on for another two centuries. Sir John Harrington (thought to give his name to 'the john') published a book in 1596 describing exactly how to construct a flushing toilet, and he had one installed for Elizabeth I in her royal palace at Richmond. Using Harrington's instructions, we re-built one of his toilets for episode two and - rather surprisingly - it was completely effective in flushing down a handful of cherry tomatoes.
However, in an age of cheap labour, it was much nicer to have your servant bring a chamber pot to your bedroom than it was for you to be obliged to walk to a shared, rather smelly, and fixed flushing toilet somewhere else in the house. Only in the nineteenth century, with the improvements to the water supply forced by the fear of cholera, and with the building of underground sewers, did the flushing toilet finally take its place in most homes.
The Living Room
Lucy Worsley in costume standing in a living room
Primarily, the living room's a place for spending your leisure hours. But it's also a place for display - a room for impressing your guests with your taste and wealth.
At its heart is the chair, originally reserved for the household's head. The original 'chairman' sat down while his servants stood, or sat upon lowly stools not chairs with arms. The notion that those in charge have the best seats is so powerful that judges still have 'benches' and professors hold 'chairs'.
With the ending of the Wars of the Roses, the defensive requirements of manor-houses declined, and grand houses began to acquire extra rooms purely for the purpose of receiving guests. Why did living rooms eventually develop so many different specialisations: drawing room, parlour, morning room, smoking room and so on? One argument suggests that new ideas about courtesy caused change: gradually it became unseemly to perform certain activities in front of other people. In the seventeenth century, the word 'disgust' was coined to describe a new revulsion that people felt towards tainted food. (Before that no one could be certain enough of the food supply that they could afford to be disgusted by anything.) They started to think that dining should have its own separate space.
Then, there was the emergence of a consumer society. As people began making things instead of growing things for a living, a multiplicity of new products and gadgets for the home appeared. And, as they bought more possessions, homeowners needed more rooms to put them in.
In a grand Elizabethan house like Hardwick Hall, there were three gigantic spaces all of which could be described as living rooms.
The first was used for receiving guests, for ceremony and formal entertainment. The enormous Long Gallery next door was for gentle exercise and the display of 37 family portraits. It also had another use: it was the only place in the entire crowded house where one could be sure of holding a private conversation, because eavesdroppers could not creep up unobserved.
But the Withdrawing Chamber at Hardwick was a slightly more exclusive space. Here, members of the family could 'withdraw' with for a more intimate party. This was the first drawing room.
For these new leisure spaces, people began to invest in textiles. The idea that a living room should be furnished with matching colours en suite first appeared in the 1660s - this was the beginning of a trend that ended in my grandmother's red velveteen three-piece suite of the 1970s.
This process of ever greater specialisation in rooms reached its high point in the nineteenth century. In the grandest Victorian houses, like Wightwick Manor in the West Midlands, we get sitting rooms and morning rooms and libraries and billiard rooms, and all of which could be described as living rooms. Today, once again, things seem to have come full circle, and the open-plan kitchen/living room/dining room made possible by the invention of the extractor fan makes many homes (including my own) much more like the single space of the medieval peasant's cottage.