Brown, 73, a native of Ireland, and Thapar, 77, of India, were selected by library staff after an extensive process that began with the receipt of nominations from all over the world.

Brown is currently on sabbatical from Princeton University to write a book examining attitudes toward wealth and poverty in the late Roman Empire.

"He is one of the most readable and literary historians of our time," Librarian of Congress James H. Billington said.

Romila Thapar, an emeritus professor of history at Jawaharlal Nehru University in New Delhi, has been called the preeminent interpreter of ancient Indian history today.

The $1 million prize for lifetime achievement in the study of humanity was endowed by Library of Congress benefactor John W. Kluge. It will be awarded in a ceremony at the library Dec. 10.