Question: Who is the mother of the person under whom the empire that invented the names of days of the week reached its greatest extent?

<P0-S0> the names of the days of the week in many languages are derived from the names of the classical planets in hellenistic astrology, which were in turn named after contemporary deities, a system introduced in the roman empire during late antiquity. <P0-S1> in some other languages, the days are named after corresponding deities of the regional culture, either beginning with sunday or with monday. <P0-S2> in the international standard iso 8601, monday is treated as the first day of the week. <SEP> <P1-S0> the maurya empire (322–185 bce) was the first empire to unify india into one state, and was the largest on the indian subcontinent. <P1-S1> at its greatest extent, the mauryan empire stretched to the north up to the natural boundaries of the himalayas and to the east into what is now assam. <P1-S2> to the west, it reached beyond modern pakistan, to the hindu kush mountains in what is now afghanistan. <P1-S3> the empire was established by chandragupta maurya in magadha (in modern bihar) when he overthrew the nanda dynasty. <P1-S4> chandragupta's son bindusara succeeded to the throne around 297 bc. <P1-S5> by the time he died in c. 272 bc, a large part of the subcontinent was under mauryan suzerainty. <P1-S6> however, the region of kalinga (around modern day odisha) remained outside mauryan control, perhaps interfering with their trade with the south. <SEP> <P2-S0> Between the 1st and 3rd centuries, the Roman Empire gradually replaced the eight - day Roman nundinal cycle with the seven - day week. <P2-S1> Our earliest evidence for this new system is a Pompeiian graffito referring to the 6th February (viii idus Februarius) of the year AD 60 as dies solis (``Sunday ''). <P2-S2> Another early witness is a reference to a lost treatise by Plutarch, written in about AD 100, which addressed the question of Why are the days named after the planets reckoned in a different order from the actual order?. <SEP> <P3-S0> Marcus Ulpius Traianus was born on 18 September 53AD in the Roman province of Hispania Baetica (in what is now Andalusia in modern Spain), in the city of Italica (now in the municipal area of Santiponce, in the outskirts of Seville). <P3-S1> Trajan's birthplace of Italica was founded as a Roman military colony of "Italian" settlers in 206BC, though it is unknown when the Ulpii arrived there. <P3-S2> Although frequently designated the first provincial emperor, and dismissed by later writers such as Cassius Dio (himself of provincial origin) as "an Iberian, and neither an Italian nor even an Italiot", Trajan appears to have hailed on his father's side from the area of Tuder (modern Todi) in Umbria, at the border with Etruria, and on his mother's side from the Gens Marcia, of an Italic family of Sabine origin. <P3-S3> It is possible, but cannot be substantiated, that Trajan's ancestors married local women and lost their citizenship at some point, but they certainly recovered their status when the city became a municipium with Latin citizenship in the mid-1st century BC. <SEP> <P4-S0> The imperial period of Rome lasted approximately 1,500 years compared to the 500 years of the Republican era. <P4-S1> The first two centuries of the empire's existence were a period of unprecedented political stability and prosperity known as the Pax Romana, or ``Roman Peace ''. <P4-S2> Following Octavian's victory, the size of the empire was dramatically increased. <P4-S3> After the assassination of Caligula in AD 41, the Senate briefly considered restoring the republic, but the Praetorian Guard proclaimed Claudius emperor instead. <P4-S4> Under Claudius, the empire invaded Britannia, its first major expansion since Augustus. <P4-S5> After Claudius' successor, Nero, committed suicide in AD 68, the empire suffered a series of brief civil wars, as well as a concurrent major rebellion in Judea, during which four different legionary generals were proclaimed emperor. <P4-S6> Vespasian emerged triumphant in AD 69, establishing the Flavian dynasty, before being succeeded by his son Titus, who opened the Colosseum shortly after the eruption of Mount Vesuvius. <P4-S7> His short reign was followed by the long reign of his brother Domitian, who was eventually assassinated. <P4-S8> The Senate then appointed the first of the Five Good Emperors. <P4-S9> The empire reached its greatest extent under Trajan, the second in this line.