Even though the Library of Congress's 1997 Country Study of Tajikistan found it difficult to definitively state the origins of the word "Tajik" because the term is "embroiled in twentieth-century political disputes about whether Turkic or Iranian peoples were the original inhabitants of Central Asia." most scholars concluded that contemporary Tajiks are the descendants of ancient Eastern Iranian inhabitants of Central Asia, in particular, the Sogdians and the Bactrians, and possibly other groups, with an admixture of Western Iranian Persians and non-Iranian peoples. According to Richard Nelson Frye, a leading historian of Iranian and Central Asian history, the Persian migration to Central Asia may be considered the beginning of the modern Tajik nation, and ethnic Persians, along with some elements of East-Iranian Bactrians and Sogdians, as the main ancestors of modern Tajiks. In later works, Frye expands on the complexity of the historical origins of the Tajiks. In a 1996 publication, Frye explains that many "factors must be taken into account in explaining the evolution of the peoples whose remnants are the Tajiks in Central Asia" and that "the peoples of Central Asia, whether Iranian or Turkic speaking, have one culture, one religion, one set of social values and traditions with only language separating them."