Technological Changes in Europe by the Eleventh Century:
During the eleventh century, Europe experienced significant technological advancements that revolutionized various aspects of society. Some key changes include:

1. Agricultural Innovations: The introduction of the heavy plow, horseshoes, and the three-field system improved agricultural productivity, leading to surplus food production and population growth.

2. Medieval Milling Technology: Water and windmills were widely adopted for grinding grain and other industrial processes, enhancing efficiency and allowing for increased production.

3. Architectural Advancements: The development of Gothic architecture, with innovations like flying buttresses and pointed arches, allowed for taller and more elaborate buildings such as cathedrals.

Effect of Technological Changes:
These technological changes had profound effects on European society during the eleventh century. Some of the major impacts include:

1. Economic Growth: The increased agricultural productivity and industrial efficiency led to economic growth, the rise of urban centers, and the development of trade networks.

2. Social Transformation: The technological advancements contributed to the growth of a middle class, increased urbanization, and the rise of specialized craftsmen and merchants.

3. Cultural Flourishing: The construction of magnificent cathedrals and other architectural marvels not only showcased the technological prowess of the time but also contributed to the flourishing of art, literature, and intellectual pursuits.
In conclusion, the technological changes that occurred in Europe during the eleventh century played a crucial role in shaping the society, economy, and culture of the time, laying the foundation for further advancements in the centuries to come.