The first known work about the structure of languages is present in early Indian Vedic texts. These texts suggest that language comprises sentences that go through four stages of evolution in three tenses—past, present, and future. Although the Greeks had an idea about language, a systematical theory about languages did not exist before the Europeans discovered the writings of Indian grammarians about language. This is why linguistics has its roots in ancient India. Moreover, religious concerns form the foundation of preservation of texts and as Buddhism spread to China and Japan, this concern for reservation of language spread to East Asia.