During the whole Byzantine era, the Emperor was the fount of authority and head of state. Beneath him and his spokesmen (the middleman between the Emperor and the services of the state) stood the government administrative machinery. One of the main features of the state organization of this period (610-867) was the militarization of the administration. This had already began in the 6th century and became systematic in the years of Justinian. Its objective was the reinforcement of those regions that had been weakened by enemy invasions, and especially those of the Danube basin. In the years of Justinian΄s successors, it evolved into the creation of the Italian (584) and the African (591) exarchates, while it was crystallized in the 8th century with the institution of the themes. Themes were called initially the 'catalogues' of the central Byzantine service, where the soldiers of a unit were registered. Later this term was used to denote the military unit itself along with the region it was based on, and, finally, it signified a geographical and administrative unit. According to this thematic organization, the general commander of every Theme assumed the military and political administration of the region under his jurisdiction. The increased authority of the strategos (general) however, did not mean that he exercised unique command directly under the Emperor. His direct subordinates, the protonotarios of the Theme (the political leader of the Theme), the praetor (the thematic judge) and the chartularios ((record keeper and the recruiting officer of the Theme) could also address the Emperor regarding thematic matters. The Themes of the period under consideration (610-867) (despite some fluctuations in their size) were the following: Anatolikon (of the East), Armeniakon (of the Armenians), Opsikiou, Optimaton, Boukellarion, Kibyrrhaioton, of the Aegean sea, of Thrace, of Macedonia, of Strymonas, of Greece, of Cephalonia, of Peloponnese, of Thessalonike, of Dyrrachion, of Sicily, of Climata-Cherson and of Crete. The themes were subdivided into smaller regions, the tourmai, which were also subdivided into smaller regions, the banda. With the thematic organization, the divisions in eparchates and dioikeseis (administrations), of the previous period were gradually abolished. In their heyday the Themes provided the state with a strong army and paved the way for following developments.