Marie's work is set squarely in the age of chivalry and 'courtly love,' a period in the Middle Ages in which political changes, a relative stability, and a cultural renaissance produced a new set of values and expectations. It is worthwhile to understand a bit of what made this time period unique to better understand Marie's lays.
The relationship between knights and their lord was nothing new. It was instead a reflection of the feudal system that guided medieval society. Feudalism is a system where the lord (or king) held the land, bequeathing it to vassals, who in exchange for that land (and other benefits) swore to provide knights to the king. The land managed by vassals was further broken into parcels (called fiefs) that were bequeathed to lower rungs of people, all the way down to peasants who farmed the land, with an expectation at each level that the lower member owed something to the higher for the privilege.
Before the age of chivalry, knighthood was uncouth and violent. In wartime, pillaging, plundering, and destruction was the expectation, with little thought of justice. Knights were typically of lower class in this period, which helps explain the rage that fueled the class.
This changed in many ways thanks to the existence of Eleanor of Aquitaine, who as the Duchess of Aquitaine wielded a notable amount of power and influence for a woman. Though she could not be monarch, her inheritance, wealth and breeding gave her special reputation, and when she married Henry II, King of England, it not only cemented a relationship with Britain and France but furthered her position whereby she could institute new changes into the aristocratic court culture of what are now known as the High Middle Ages.
Coming both from a love of literary work (she was a patron of many great medieval writers, most notably Chretien de Troyes) and her unique vantage as a woman, Eleanor proposed changes that were extremely popular. In her new conception of 'courtly love,' knights were now to be considered a noble class, expected to further their reputation through noble adventures while seeking the proper woman to whom they would be faithful and courtly. The modern idea of 'chivalry' – whereby a man treats a woman with respect – certainly derives from this concept, though Eleanor's sense of chivalry had much more game-play involved. The quests were more complicated games belied by the position of women as prizes. Of course, it was still a step forward from the age of warrior-knights that had preceded chivalry. During this period, classic legends (particularly those of King Arthur) were reinvented to sell the concept of chivalrous behavior and adventures to the noble class. Vassals began to offer themselves as knights, not only because it afforded them opportunities to compete on this new stage but also because there was less war that threatened to destroy them.
It is a fascinating period that Marie aims both to celebrate and also subtly criticize. Its faults are satirized throughout the lays, perhaps because Marie herself had an interesting vantage as a woman writer from which to observe how the next stage of development for women might go.