No, not all peasants under the feudal system were serfs. While serfs were the predominant agricultural labourers in many parts of Europe, there existed a distinction between serfs and free peasants. Serfs were tied to the land, owing their labour and a portion of their produce to the lord. They couldn't leave or sell their land without the lord's permission. Free peasants, on the other hand, enjoyed more rights. They might own their land or rent it, and they had the freedom to move or sell their land. Their obligations to a lord were often less restrictive, usually limited to paying rent or taxes.

Guilds were associations of craftsmen or merchants in medieval towns and cities. They played an integral role in regulating trade, setting standards for goods, determining prices, and ensuring the welfare of their members. Guilds often had the authority to set rules for training, such as establishing apprenticeship durations and criteria for becoming a master craftsman. They also acted as a social safety net, providing support to members in times of sickness or financial distress. Furthermore, guilds held significant sway in urban politics, with many having the right to send representatives to municipal councils, ensuring that the interests of their members were well-represented in local governance.

The merchant class, particularly as the medieval period progressed, began challenging traditional social hierarchies. With the decline of feudalism and the rise of cities, trade routes expanded, leading to greater economic opportunities. Merchants capitalised on these opportunities, amassing wealth independent of land ownership. Their increasing wealth allowed them to fund infrastructural projects, sponsor cultural endeavours, and even influence politics. As a result, they began to attain social status, often rivalling or even surpassing the traditional nobility in influence. Their rise also introduced the concept of upward mobility based on merit and wealth rather than mere heredity.

Under manorialism, the lord owned the estate or manor, and serfs worked the land. Serfs were not free individuals; they were tied to the land and couldn't move or change their vocation without the lord's consent. In return for their labour, serfs received protection, the right to cultivate certain plots for their sustenance, and access to common resources. It was a symbiotic relationship: lords needed serfs to work the land and produce goods, while serfs depended on lords for protection and a means of livelihood. This system, while exploitative, provided stability in a time marked by frequent wars and invasions.

The rise of cities played a pivotal role in undermining the feudal system. Cities became centres of commerce, education, and culture, offering a sharp contrast to the agrarian, manorial life of the countryside. The urban environment provided greater opportunities for employment beyond farming, and this economic diversification eroded the traditional land-based power of the nobility. As cities grew in wealth and influence, they often obtained charters that granted them certain rights and freedoms, effectively bypassing the authority of local lords. Additionally, cities became melting pots where ideas, including those challenging feudal norms, circulated freely, contributing to a shift in societal perceptions and values.