In the Middle Ages, upper class Britons and other European nobility in castles or large manor houses dined in the Great Hall.
This was a large multi-function room capable of seating the bulk of the population of the house. The family would sit at the head table on a raised dais, with the rest of the population arrayed in order of diminishing rank away from them. Tables in the great hall would tend to be long trestle tables with benches. The sheer number of people in a Great Hall meant it would probably have had a busy, bustling atmosphere. Suggestions that it would also have been quite smelly and smoky are probably, by the standards of the time, unfounded. These rooms had large chimneys and high ceilings and there would have been a free flow of air through the numerous door and window openings.
It is true that the owners of such properties began to develop a taste for more intimate gatherings in smaller 'parlers' or 'privee parlers' off the main hall but this is thought to be due as much to political and social changes as to the greater comfort afforded by such rooms. In the first instance, the Black Death that ravaged Europe in the 14th Century caused a shortage of labour and this had led to a breakdown in the feudal system. Also the religious persecutions following the dissolution of the monasteries under Henry VIII made it unwise to talk freely in front of large numbers of people.
Over time, the nobility took more of their meals in the parlour, and the parlour became, functionally, a dining room (or was split into two separate rooms). It also migrated farther from the Great Hall, often accessed via grand ceremonial staircases from the dais in the Great Hall. Eventually dining in the Great Hall became something that was done primarily on special occasions.
Toward the beginning of the 18th Century, a pattern emerged where the ladies of the house would withdraw after dinner from the dining room to the drawing room. The gentlemen would remain in the dining room having drinks. The dining room tended to take on a more masculine tenor as a result.