Basil became bishop of Caesarea in 370, during a famine, and the works he is remembered for in his own city were material. On land outside the walls he built a complex with a church, a residence for clergy, lodging for travellers, workshops in which the poor could be given a trade, and quarters for the sick, including a separate provision for lepers, whom he is recorded as having touched and cared for himself. Gregory of Nazianzus, describing it after Basil's death, calls it a new city. Later writers call it the Basiliad. It is regularly cited as one of the earliest institutional hospitals of the Christian world, though the claim that it was the first requires more care than it usually receives.
His doctrinal work belongs to the long argument after Nicaea. The treatise On the Holy Spirit defends the Spirit's full divinity, and does so partly by an argument from how the church already prays, on the ground that a practice held everywhere carries weight even where a scriptural proof text is contested. The position was settled at Constantinople in 381, two years after he died.
The second eucharistic liturgy of the Byzantine rite bears his name and is served on about ten days of the year, chiefly the Sundays of Lent, the eves of Christmas and Epiphany, and his own feast. Robert Taft's history of the rite treats the connection between Basil and the anaphora as real in origin, while stressing that the text as it is served has been reworked repeatedly and is not simply his composition.