III.--Life at Caesarea; Baptism; and Adoption of Monastic Life.
When Basil overcame the efforts of his companions to detain him at Athens, Gregory was prevailed on to remain for a while longer. Basil therefore made his rapid journey homeward alone. His Letter to Eustathius  alleges as the chief reason for his hurried departure the desire to profit by the instruction of that teacher. This may be the language of compliment. In the same letter he speaks of his fortitude in resisting all temptation to stop at the city on the Hellespont. This city I hesitate to recognise, with Maran, as Constantinople. There may have been inducements to Basil to stop at Lampsacus and it is more probably Lampsacus that he avoided.  At Caesarea he was welcomed as one of the most distinguished of her sons,  and there for a time taught rhetoric with conspicuous success.  A deputation came from Neocaesarea to request him to undertake educational work at that city,  and in vain endeavoured to detain  him by lavish promises. According to his friend Gregory, Basil had already determined to renounce the world, in the sense of devoting himself to an ascetic and philosophic life.  His brother Gregory, however,  represents him as at this period still under more mundane influences, and as shewing something of the self-confidence and conceit which are occasionally to be observed in young men who have just successfully completed an university career, and as being largely indebted to the persuasion and example of his sister Macrina for the resolution, with which he now carried out the determination to devote himself to a life of self-denial. To the same period may probably be referred Basil's baptism. The sacrament was administered by Dianius.  It would be quite consonant with the feelings of the times that pious parents like the elder Basil and Emmelia should shrink from admitting their boy to holy baptism before his encountering the temptations of school and university life.  The assigned date, 357, may be reasonably accepted, and shortly after his baptism he was ordained Reader.  It was about this that he visited monastic settlements in Palestine, Mesopotamia, Coele Syria, and Egypt,  though he was not so fortunate as to encounter the great pope Athanasius.  Probably during this tour he began the friendship with Eusebius of Samosata which lasted so long.
 Ep. i.
 What these inducements can have been it seems vain to conjecture. cf. Ep. i. and note.
 Greg. Naz., Or. xliii.
 Rufinus xi. 9.
 Ep. ccx. S: 2. The time assigned by Maran for the incident here narrated is no doubt the right one. But the deputation need have travelled no farther than to Annesi, if, as is tolerably certain, Basil on his return from Athens visited his relatives and the family estate.
 The word kataschein would be natural if they sought to keep him in Pontus; hardly, if their object was to bring him from Caesarea.
 Or. xliii.
 Vit. Mac.
 cf. De Sp. Scto. xxix., where the description of the bishop who both baptized and ordained Basil, and spent a long life in the ministry, can apply only to Dianius. cf. Maran, Vit. Bas. iii.
 According to the legendary life of St. Basil, attributed to St. Amphilochius, he was baptized at Jerusalem. Nor is it right to omit to notice the argument of Wall (Infant Baptism, ch. x.) founded on a coincidence between two passages in the writings of Greg. Naz. In Or. xl. ad init. he speaks of baptism as a genesis hemerine kai eleuthera kai lutike pathon, pan to apo geneseos kalumma peritemnousa, kai pros ten ano zoen epanagousa. In Or. xliii., he says of Basil that ta prota tes helikias upo to patri...sparganoutai kai diaplattetai plasin ten aristen te kai katharotaten, hen hemerinen ho theios Dabid kalos onouazei kai tes nuchterines antitheton. As they stand alone, there is something to be said for the conclusion Wall deduces from these passages. Against it there is the tradition of the later baptism, with the indication of Dianius as having performed the rite in the De Sp. Scto. 29. On the other hand ta prota tes helikias might possibly refer not to infancy, but to boyhood.
 De S. Scto. xxiv. On his growing seriousness of character, cf. Ep. ccxxiii.
 Epp. i. and ccxxiii. S: 2.
 Ep. lxxx.
Reference address : https://www.elpenor.org/basil/life-works.asp?pg=8