<論説>コムネノス朝の成立 : 一一世紀ビザンツ帝国の政治体制

Abstract

一一世紀のビザンツ帝国は一〇八一年のコムネノス朝成立を大きな転機として、それ以前は混乱・衰退の、それ以降は再建・繁栄の時代である。本論文はこの転換を帝国政治体制の変化という観点からとらえなおそうとするものである。一一世紀の混乱時代は、前世紀以来成長を続け、ついに帝位を左右する力をもつに至った大土地所有貴族間の権力闘争の時代であり、帝国の伝統的な皇帝独裁制は重大な修正を要求されていた。危機の基因はここにあり、一一世紀ビザンツ帝国の歴史は彼らの動向を基軸としてとらえるべきである。皇帝権をめぐる有力貴族間の抗争において、皇帝絶対権の理念に対抗するという形で現われたのは古い「選挙王政」的皇帝理念であった。この「選挙王政」の理念は現実には有力貴族の連合支配体制の樹立をめざすものとなる。一〇五七年のイサキオス・コムネノスの反乱から即位の過程において芽ばえながらも挫折した、この貴族連合支配体制は、一〇八一年のアレクシオス・コムネノスを中心とする反乱の結果実現されるに至った。この帝国政治体制の変換こそが、一〇八一年以降の再建・繁栄の第一の要因であった。

After the death of Basil II (1025), Byzantine Empire entered upon the period of troubles, frequent changes of rulers, and general decline. It ended with the accession of Alexius Comnenus, the founder of the dynasty of Comneni (1081-1185), and since then the Byzantine Empire kept its position as a great power for a hundred years. The accession of Alexius Comnenus has been regarded as the triumph of the military nobility of the provinces over the civil nobility of the capital. It is also asserted that the use of the pronoia for military ends was the main reason why the Byzantine Empire strengthened its defences under the dynasty of Comneni, the rule of the military nobility. But these interpretations seem to me of dubious validity. Two opposing factions of the nobility, military and civil, belong one and the same social class, the landed aristocracy and their opposition is superficial. Besides, informations of pronoia are very scanty in Comnenian period. This paper will therefore be devoted to attempt at another interpretation of the reconstruction of the Byzantine Empire after 1081. In the llth century landed aristocracy fought amongst themselves as to who of them should take control. This is the real reason why the Empire declined so rapidly in this period. We can therefore make the Byzantine history in the llth century clearer by examining the relation between the Emperor and the landed aristocracy. I will pay special attention to two principles of the imperial accession; election by constitutional elements and hereditary principle. The former, which was older than the latter, was once again put forward in this time of troubles, when the election principle meant the opposition to the traditional monarchy and its aim was to establish the joint rule of landed aristocracy. In 1057 Isaac Comnenus, uncle of Alexius, was proclaimed Emperor by the landed aristocracy of Asia Minor. In spite of the opposition of his supporters, however, he accepted the proposal of Emperor Michael VI that he should be adopted by the Emperor and recognized the heir to the throne. Soon he was crowned Emperor, but he ruled only from 1057 to 1059, hostile aristocrats plotted a conspiracy against him. Twenty four years later Alexius Comnenus was proclaimed Emperor and came to the throne as the result of the alliance of many landed aristocrats. The joint rule of the landed aristocracy had been realized this time. Comparing the accessions of Isaac and Alexius Comnenus, I came to the conclusion that the reconstruction after 1081 should be ascribed to the joint rule of the landed aristocracy which, after the struggles amongst themselves, was realized in the revolution of 1081.