Lu (, c. 1042–249 BC) was a vassal state during the Zhou dynasty of ancient China located around modern Shandong province. Founded in the 11th century BC, its rulers were from a cadet branch of the House of Ji (姬) that ruled the Zhou dynasty. The first duke was Boqin, a son of the Duke of Zhou, who was brother of King Wu of Zhou and regent to King Cheng of Zhou. Lu was the home state of Confucius as well as Mozi, and as such has an outsized cultural influence among the states of the Eastern Zhou and in history. The Annals of Spring and Autumn, for instance, was written with the Lu rulers' years as their basis. Another great work of Chinese history, the Zuo Zhuan or Commentary of Zuo, was also written in Lu by Zuo Qiuming. The state's capital was in Qufu and its territory mainly covered the central and southwest regions of what is now Shandong Province. It was bordered to the north by the powerful state of Qi and to the south by the powerful state of Chu. The position of Lu on the eastern frontiers of the Western Zhou state, facing the non-Zhou peoples in states such as Lai and Xu, was an important consideration in its foundation. William H. Baxter (apud Matisoff, 1995) suggests a semantic connection between the toponym 魯 Lǔ and its homophone 鹵 lǔ "salty, rock salt" (< OC *C-rāʔ) since that region was a salt marsh in ancient times. Lu was one of several states founded in eastern China at the very beginning of the Zhou dynasty, in order to extend Zhou rule far from its capital at Zongzhou and power base in the Guanzhong region. Throughout Western Zhou times, it played an important role in stabilising Zhou control in modern-day Shandong. During the early Spring and Autumn period, Lu was one of the strongest states and a rival of Qi to its north. Under Duke Yin and Duke Huan of Lu, Lu defeated both Qi and Song on several occasions. At the same time, it undertook expeditions against other minor states. This changed by the middle of the period, as Lu's main rival, Qi, grew increasingly dominant.