The 10th century is the period from 901 to 1000 in accordance with the Julian calendar, and the last century of the 1st millennium. In China the Song Dynasty was established. The Muslim World, experienced a cultural zenith, especially in Spain under the Caliphate of Córdoba. Additionally, the 10th century was the zenith for the Byzantine and Bulgarian Empires. Medievalist and historian of technology Lynn White said that “to the modern eye, it is very nearly the darkest of the Dark Ages”, but concluded that “. . . if it was dark, it was the darkness of the womb.” Similarly, Helen Waddell wrote that the 10th century was that which “in the textbooks disputes with the seventh the bad eminence, the nadir of the human intellect.” In the 15th century, Lorenzo Valla described it as the Century of Lead and Iron and later Cardinal Baronius as the Leaden Century or Iron Century. According to one estimate, the tenth century saw fewer deaths in war (as a percentage of the total population) than any other century since 3000 B.C.