The Agricultural Revolution of Solethania
With the invention and subsequent widespread use of more efficient golems replacing physical workers in agriculture, there has been a massive shift out of subsistence labor, as the agricultural output outstripped population growth and demand, creating large surpluses of food and manpower in an exceptionally short amount of time.
Kingdoms, guilds, and religious orders quickly and competitively vied for this new pool of manpower, and a strong and mobile middle class formed.
Kingdoms were able to create and maintain standing armies and expand their influence. Guilds were able to begin a process not unlike industrialization (standardization of crafting, organized exploration and adventuring, etc.), and the religious orders were able to expand and begin educating the general populous in scientific/magic theory, knowledge, and philosophical thought.
Despite the massive changes and societal upheaval this brought, many things remained the same. Feudalistic society grew more entrenched, as only the nobility and religious orders owned land -the very land the golems (that only the wealthy can truly afford) now work that provide the food for the populous. And the new and powerful standing armies worked well to prevent and quell revolts or rebellions against the established order.