From the beginning of the 17th century to the middle of the 19th century the Christian Empire of Ethiopia was in decline; the power and prestige of the Emperor were at a low ebb and the provincial governors vied with one another for a dominant position in Empire. This decline was the combined effect upon the Empire of past wars with her Muslim neighbours, religious civil war and the Galla invasions. At the provincial level the period was marked by territorial expansion, centralization and consolidation of provincial autonomy. This development achieved varying degrees of success in the different provinces. Probably the highest degree of success was achieved in the Galla-dominated province of Shoa, where a line of Amhara rulers the district of Manz succeeded in establishing a stable dynasty. Through military prowess and administrative ability the dynasty gradually conquered the surrounding Galla, and by the 1840s had created a powerful kingdom independent of the Emperor. The success of Shoa's development was due partly to the ability of its rulers, partly to the absence of interference from other princes in the Empire, and party to the political and military weakness of the Galla tribes. In 1855-6 Emperor Theodros, having revived the imperial authority, conquered Shoa but nine years later Shoa regained her independence. From 1865 to 1889 the relations between Shoa and the revitalized Imperial power became a crucial domestic issue in the Empire. The period also saw Shoa conquer more Galla provinces. As a result of her expansion there evolved in Shoa a strong centralized administration, and a commercial and military activity, the relative efficiency of which enabled the kingdom to withstand efforts by the Imperial power to conquer it. In 1889 the King of Shoa became Emperor and thereby re-united the Empire under the Shoan. dynasty.