Final answer:
Engineer Libanos's work on the Lalibela Church Complex was pivotal in both the community's economic prosperity due to pilgrimage activity and in reinforcing the spiritual structure of Ethiopian Christian faith through these monumental rock-hewn churches.
Step-by-step explanation:
The work of the engineer Libanos on the Lalibela Church Complex, carved directly out of bedrock in northern Ethiopia, is of immense significance both economically and spiritually. These structures, attributed to King Lalibela's era (1181-1221), are not only architectural marvels from the 12th and 13th centuries but also integral to the religious and economic vitality of the community. As master masons, engineers like Libanos were responsible for overseeing the construction of these monolithic churches, employing practical geometry and arithmetic without modern engineering theory.
Further, the churches of Lalibela served as an important pilgrimage destination, contributing to local economic prosperity as pilgrims required food and lodging. The spiritual relevance is deeply rooted in the Christian faith, with the church acting as a symbol of rebirth and hope after death. The creation of such spiritual and economic centers would have significant impacts on the culture and demeanor of the society surrounding them, fostering a thriving artistic tradition, such as the illuminated manuscripts and liturgical objects that have been found as offerings in these churches.