The court quickly assumed a pious and austere atmosphere under her influence, befitting her almost monastic life style. On [[July 4]], 414, the Senate proclaimed her augusta (empress) and made her regent for her brother. When Theodosius became capable of ruling by himself in 416, Pulcheria continued to strongly influence over her brother and of the course of the empire. Through her influence Theodosius removed all pagans from the civil service. Under her influence Theodosius and his wife Aelia Eudoxia, who had been a pagan, became devout Christians.
Pulcheria used her wealth for the [[Church]]. In doing so she inspired her brother to do likewise. While she appeared to be indifferent to the [[Arianism]]
was practiced by the German tribes, she took a firm position on the heretical teaching of [[Nestorius]]. She almost immediately showed her antagonism towards him when he became [[patriarch]] in 428. Whether the downgrading of the status of the Virgin Mary from Theotokos to Christotokos under Nestorianism was involved, Pulcheria greatly influenced her brother's position in the controversies that led up to the [[Third Ecumenical Council|Council in Ephesus]] in 431. At first he was a supporter of Nestorius before acceding to his sister's position. In this controversy Patr. [[Cyril of Alexandria]] believed Pulcheria's influence was important in the downfall of his rival.
In 441, Pulcheria's influence on her brother began to wain as the eunuch Chrysaphius convinced Theodosius to dismiss his sister. But soon the [[Monophysitism|Monophysite]] controversy was raised by the [[archimandrite]] Eutyches and supported by Theodosius as well as by Cyril's successor as [[Patriarchs of Alexandria|patriarch of Alexandria]], [[Dioscorus of Alexandria|Dioscorus]]. When Eutyches' views were validated at the 'Robber Council' of 449 in Ephesus, [[Leo the Great|Pope Leo I of Rome]] included Pulcheria among those he approached for help in reversing the council's decisions.