"superlatively sacred or inviolable," c. 1600, from Latin sacrosanctus "inviolable, protected by religious sanction, consecrated with religious ceremonies," from sacro, ablative of sacrum "religious sanction, religious rite" (from neuter singular of sacer "sacred") + sanctus, past participle of sancire "make sacred" (for both, see sacred). Earlier in partially Englished form sacro-seint (c. 1500).
early 15c., earlier asile (late 14c.), "place of refuge, sanctuary," from Latin asylum "sanctuary," from Greek asylon "refuge, fenced territory," noun use of neuter of asylos "inviolable, safe from violence," especially of persons seeking protection, from a- "without" (see a- (3)) + sylē "right of seizure," which is of unknown etymology.
Literally, "an inviolable place." Formerly a place where criminals and debtors sought shelter from justice and from which they could not be taken without sacrilege. General sense of "safe or secure place" is from 1640s; abstract sense "inviolable shelter, protection from pursuit or arrest" is from 1712. Meaning "benevolent institution to shelter some class of persons suffering social, mental, or bodily defects" is from 1773, originally of female orphans.
"chaste, pure, virgin," 1590s, originally (early 15c.) "belonging to or dedicated to Vesta," Roman goddess of hearth and home, from Latin vestalis. The noun is recorded from 1570s, short for Vestal virgin, one of four (later six) priestesses (Latin virgines Vestales) in charge of the sacred fire in the temple of Vesta in Rome. From 1580s in reference to any virgin or chaste woman.
They entered the service of the goddess at from six to ten years of age, their term of service lasting thirty years. They were then permitted to retire and to marry, but few did so, for, as vestals, they were treated with great honor, and had important public privileges. Their persons were inviolable, any offense against them being punished with death, and they were treated in all their relations with the highest distinction and reverence. A vestal who broke her vow of chastity was immured alive in an underground vault amid public mourning. There were very few such instances; in one of them, under Domitian, the chief of the vestals was put to death under a false charge trumped up by the emperor. [Century Dictionary]