Meanwhile the purely Sumerian city of Lagash had similarly grown powerful and aggressive. For a time it acknowledged the suzerainty of Kish, but ultimately it threw off the oppressor's yoke and asserted its independence. The cumulative efforts of a succession of energetic rulers elevated Lagash to the position of a metropolis in Ancient Babylonia. The goddess Bau, "the mother of Lagash", was worshipped in conjunction with other deities, including the god Nin-Girsu, an agricultural deity, and therefore a deity of war, who had solar attributes. One of the titles of Nin-Girsu was En-Mersi, which, according to Assyrian evidence, was another name of Tammuz, the spring god who slew the storm and winter demons, and made the land fertile so that man might have food. Nin-Girsu was, it would seem, a developed form of Tammuz, like the Scandinavian Frey, god of harvest, or Heimdal, the celestial warrior. Bau was one of the several goddesses whose attributes were absorbed by the Semitic Ishtar. She was a "Great Mother", a creatrix, the source of all human and bestial life, and, of course, a harvest goddess. She was identified with Gula, "the great one", who cured diseases and prolonged life. Evidently the religion of Lagash was based on the popular worship of the "Queen of Heaven", and her son, the dying god who became "husband of his mother". The first great and outstanding ruler of Lagash was Ur-Nina, who appears to have owed his power to the successful military operations of his predecessors. It is uncertain whether or not he himself engaged in any great war. His records are silent in that connection, but, judging from what we know of him, it may be taken for granted that he was able and fully prepared to give a good account of himself in battle. He certainly took steps to make secure his position, for he caused a strong wall to be erected round Lagash. His inscriptions are eloquent of his piety, which took practical shape, for he repaired and built temples, dedicated offerings to deities, and increased the wealth of religious bodies and the prosperity of the State by cutting canals and developing agriculture. In addition to serving local deities, he also gave practical recognition to Ea at Eridu and Enlil at Nippur. He, however, overlooked Anu at Erech, a fact which suggests that he held sway over Eridu and Nippur, but had to recognize Erech as an independent city state.