History of the Republic of Venice of the Sea" ceremony was established in this period. Orseolo died in 1008. Venice's control over the Adriatic was strengthened by an expedition by Pietro's son Ottone in 1017, by which time Venice had assumed a key role in balancing power between the Byzantine and Holy Roman Empires. During the long Investiture Controversy, an 11th-century dispute between Henry IV, Holy Roman Emperor and Pope Gregory VII over who would control appointments of church officials, Venice remained neutral, and this caused some attrition of support from the Popes. Doge Domenico Selvo intervened in the war between the Normans of Apulia and
Gulf of Finland depression was somewhat reshaped by glacier's activities. Its retreat formed the Littorina Sea, whose water level was some 7–9 metres higher than the present level of the Baltic Sea. Some 4,000 years ago the sea receded and shoals in the gulf have become its islands. Later uplifting of the Baltic Shield skewed the surface of the gulf; for this reason, its ancient northern shores are significantly higher than the southern ones. The climate in the area is humid continental climate, characterized by temperate to hot summers and cold, occasionally severe winters with regular precipitation. The vegetation is dominated by a