9th–12th centuries
During the 9th and early 10th centuries, Hellas suffered from Saracen raids, especially after the conquest of Crete by the Arabs in the 820s and the establishment of the Emirate of Crete. Among the major such events, in the 880s the Arab emir of Tarsus attacked Euripos (Chalcis) but was defeated, and in 902 the Saracens under the renegade Damian of Tarsus sacked the port city of Demetrias. Ten ships from Hellas also participated in the failed attempt to recover Crete under Himerios in 911/2. In 918 and again in 923, the area was subjected to Bulgarian raids under Tsar Simeon that reached even into the Peloponnese and may have destroyed Thebes. Nevertheless, from the late 9th century on Hellas, along with the rest of Greece, shows evidence of increased prosperity, such as the increase in coinage, foundation of new towns and the establishment of new industries (most notably the silk industry in Thebes). The Saracen threat receded during the 10th century and was practically ended as the result of the Byzantine reconquest of Crete in 960–961, but the Bulgarian threat was renewed under Tsar Samuel, who occupied Thessaly in 986 and launched several devastating raids into Central Greece and the Peloponnese until his defeat at the Battle of Spercheios in 997.
During the 10th and 11th centuries, Hellas was often governed jointly with the Peloponnese under a single strategos, and as the civilian administration rose in importance, the same practice appears there as well, with protonotarioi, praetores and kritai being appointed for both themes. Thessaly appears to have been detached from Hellas and joined to the theme of Thessalonica from the early 11th century—though the Spercheios valley remained part of Hellas—until sometime in the 12th century. The strategos of Hellas is still attested for much of the 11th century, and a doux of Thebes and Euripus after the middle of the 12th century. By the end of the 11th century, the joint administration of Hellas and the Peloponnese came under the control of the megas doux, the commander-in-chief of the Byzantine navy. Due to the latter's absence from the province, however, the local administration remained under the local praetor, a position often held during this period by senior and distinguished officials like the legal scholars Alexios Aristenos and Nicholas Hagiotheodorites. Increasingly, however, smaller jurisdictions appeared within the boundaries of both themes. These eventually evolved into the smaller fiscal districts variously termed horia (sing. horion), chartoularata (sing. chartoularaton), and episkepseis (sing. episkepsis) in the 12th century, while the old themes of Hellas and the Peloponnese gradually withered away as administrative entities. The horia in particular are only attested for Greece, and appear to have been based at Larissa, Thebes and Euripus, Athens, Corinth, and Patras.
The 11th century was largely a period of peace for southern Greece, interrupted only by raids during the uprising of Petar Delyan (1040–1041), a raid by the Turkic Uzes tribe in 1064, and the unsuccessful Norman attacks into Thessaly in 1082–1083. The Italian maritime republics, with the Republic of Venice first and foremost, began to establish their presence in the region towards the end of the century, signalling the beginning of the Italians' ascendancy in maritime commerce and their gradual takeover of the Byzantine economy: in the aftermath of the failed Norman invasion, Alexios I granted the first trading privileges to the Venetians in exchange for their naval aids against Norman fleets, such as immunity from taxation and the right to set up trade colonies in certain towns including Constantinople itself. In Hellas itself Euripus, Thebes, and Athens were among those towns. Alexios' successors tried to curb these privileges with successes in part — and leading to the Venetian sacking of Euripus in 1171 in retaliation - but in 1198 Alexios III Angelos (r. 1195–1203) was forced to concede even more extensive ones, allowing the Venetians to create trade stations virtually in all cities situated close to the coast.
In 1148, the Normans under Roger II of Sicily plundered Thebes, carrying off its silk workers to Palermo. The local silk industry survived, however, and was revived, partly if not mostly with Jewish workers as attested by Benjamin of Tudela in his visit in 1165. Both Benjamin and the Arab geographer al-Idrisi describe central Greece during the middle of the 12th century as densely populated and prosperous, while Benjamin records the presence of Jewish communities in Thebes, Krisa, Euripus, Ravenica, and Zetouni (Lamia). The situation began to change towards the end of the reign of Manuel I Komnenos (r. 1143–1180), whose costly military ventures led to a hike in taxation. Coupled with the corruption and autocratic behaviour of officials, this led to a decline in industry and the impoverishment of the peasantry, eloquently lamented by the Metropolitan of Athens, Michael Choniates. This decline was temporarily halted under Andronikos I Komnenos (r. 1182–1185), who sent the capable Nikephoros Prosouch as praetor, but resumed after Andronikos' fall.
At the turn of the 13th century the Byzantine Empire's decay was in full swing. In the northwestern Peloponnese, Leo Sgouros, ruler of Nauplia, had already taken over Argos and Corinth, and launched raids into Attica. Taking advantage of the preoccupation of the imperial authorities with the Fourth Crusade, in 1204 he captured Athens, before taking over Boeotia and Thessaly without a fight. Having become the master of a quasi-independent realm encompassing much of southern Greece he then tried to legitimize his position by marrying the daughter of the deposed Alexios III Angelos at Larissa. Following the sack of Constantinople by the Crusaders in April 1204, however, the situation changed: in the same autumn, Boniface of Montferrat led a crusader army into Thessaly. Leo Sgouros tried to confront the Crusaders at the Thermopylae, but his soldiers ran away, and he retreated to his fortress bases in the Peloponnese, from where he resisted for a few more years. Boniface divided the captured lands among his followers; the main Latin states formed in the former area of Hellas were the Duchy of Athens, the Marquisate of Bodonitsa, parts of the Kingdom of Thessalonica, the Lordship of Salona, and the Triarchy of Negroponte.
