Question: Saint Constantine developed the main administrative divisions of what?

<P0-S0>  He was the son of Flavius Valerius Constantius, a Roman Army officer, and his consort Helena. <P0-S1>  His father became "Caesar", the deputy emperor in the west, in 293 AD. <P0-S2>  Constantine was sent east, where he rose through the ranks to become a military tribune under Emperors Diocletian and Galerius. <P0-S3> Constantine the Great (Latin: "Flavius Valerius Aurelius Constantinus Augustus" ; Greek: Κωνσταντῖνος ὁ Μέγας ; 27 February 272 AD – 22 May 337 AD), also known as Constantine I or Saint Constantine (in the Orthodox Church as Saint Constantine the Great, Equal-to-the-Apostles), was a Roman Emperor of Illyrian-Greek origin from 306 to 337 AD. <P0-S4>  In 305, Constantius raised himself to the rank of "Augustus", senior western emperor, and Constantine was recalled west to campaign under his father in Britannia (Britain). <P0-S5>  Constantine was acclaimed as emperor by the army at Eboracum (modern-day York) after his father's death in 306 AD, and he emerged victorious in a series of civil wars against Emperors Maxentius and Licinius to become sole ruler of both west and east by 324 AD. <SEP> <P1-S0>  They were established in the mid-7th century in the aftermath of the Slavic invasion of the Balkans and Muslim conquests of parts of Byzantine territory, and replaced the earlier provincial system established by Diocletian and Constantine the Great. <P1-S1>  In their origin, the first themes were created from the areas of encampment of the field armies of the East Roman army, and their names corresponded to the military units that had existed in those areas. <P1-S2> The themes or themata (Greek: θέματα ; singular θέμα, "thema") were the main administrative divisions of the middle Eastern Roman Empire. <P1-S3>  The theme system reached its apogee in the 9th and 10th centuries, as older themes were split up and the conquest of territory resulted in the creation of new ones. <P1-S4>  The original theme system underwent significant changes in the 11th and 12th centuries, but the term remained in use as a provincial and financial circumscription until the very end of the Empire. <SEP> <P2-S0> Agios Konstantinos (Greek: Άγιος Κωνσταντίνος meaning Saint Constantine, before 1954: Καμάριζα - "Kamariza") is a village and a former community in East Attica, Greece. <P2-S1>  Since the 2011 local government reform it is part of the municipality Lavreotiki, of which it is a municipal unit. <P2-S2>  It was named after Saint Constantine. <SEP> <P3-S0> Constantine Bay (Cornish: Eglos Costentin , meaning "church of St Constantine") is a village and beach on the Atlantic coast of north Cornwall, England, United Kingdom. <P3-S1>  It is situated approximately three miles (5 km) west of Padstow and is in the parish of St Merryn. <P3-S2>  The beach is popular with surfers and has lifeguard patrols in the summer. <P3-S3>  Constantine Bay is named after Saint Constantine, a 6th-century Cornish saint possibly identified with a minor British king Constantine. <P3-S4>  St Constantine's Well, an historic site, is accessible by public right of way on Trevose Golf Club's golf course. <P3-S5>  The area was a favourite holiday location of Margaret Thatcher during her premiership and also of former Prime Minister David Cameron.