Neustria (nōōs´trēə), western portion of the kingdom of the Franks in the 6th, 7th, and 8th cent., during the rule of the Merovingians. It comprised the Seine and Loire country and the region to the north; its principal towns were Soissons and Paris. The realm originated with the several partitions of the lands of Clovis I (d. 511) among his sons and grandsons during the 6th cent. The dynastic rivalry involved Neustria in almost constant warfare with the eastern portion of the Frankish kingdom, which became known as Austrasia. The conflict culminated in the long and bitter war between Queen Fredegunde of Neustria (d. 597) and Queen Brunhilda of Austrasia (d. 613). Neustria and Austrasia were reunited briefly by Clotaire I, Clotaire II, and Dagobert I. After Dagobert the kings sank to insignificance, while the mayors of the palace rose in power. In 687, Pepin of Heristal, mayor of the palace of the king of Austrasia, defeated his Neustrian rival and united Austrasia and Neustria. His descendants, the Carolingians, continued to rule the two realms, first as mayors and after 751 as kings.