Synagogues have rarely conformed to stylistic rules anywhere in the world or, as a building type, been resolved in unique or recognizable terms. Most of the buildings in India are no exception. In contrast are the synagogues built by the Cochin Jews of Kerala, India. Influenced by Indian building traditions coupled with the influences of visiting merchants and imperialists over the centuries, the Cochin synagogues constitute wonderful examples of the vernacular ""thachusasthra"" design of Kerala. Until the 16th century and the arrival of the Portuguese in India, roofs of local buildings were often bamboo framed and covered with thatched palm leaves—this technique continues to be prevalent in Kerala's villages even today. The roof system would have been set on mud walls or atop simple masonry walls that were finished in smooth veneers. In time, this construction technique was replaced with wood framed roofs (often teak) covered with flat terracotta tiles together supported by thick laterite stone walls (a local material) veneered in ""chunam"", a polished lime plaster. The local components were thus fused with foreign building techniques introduced by outsiders, namely the Portuguese and later the Dutch. These influences also impacted synagogue architecture and were combined with the Jewish ritual and liturgical requirements.