The philosophy and religion of the Tlingit, although never formally codified, was historically a fairly well organized philosophical and religious system whose basic axioms shaped the way all Tlingit people viewed and interacted with the world around them. Between 1886 and 1895, in the face of their shamans' inability to treat Old World diseases, including smallpox, many Tlingit people converted to Orthodox Christianity. It has been argued that they saw Eastern Orthodox Christianity as a way of resisting assimilation to the "American way of life", which was associated with Presbyterianism. Russian Orthodox missionaries had translated their liturgy into the Tlingit language. After Christianization, the Tlingit belief system began to erode.