PietasThe classic Roman virtue of pietas, as in "pius Aeneas," meant "devotion to duty," especially in regards to the gods, country and family. The related virtues, then, were religion, patriotism, and devotion to family. In Antigone it is precisely a perceived tension between the three duties that is at the heart of the drama. Antigone's choice hinges on an attempt to hierarchize the virtues. In fact, the tension was false, since Creon's decree was unjust. In later medieval Latin it came to mean "loving devotion," as in "O clemens! o pia! o dulcis virgo Maria!" and "pie Jesu." In English "piety" came to mean a tendency to displays of external religious devotion. In the term "pietist" it meant a preference for emotions over thought in religious practice.
It would be nice to see a resurrection of this Roman virtue. First of all, it points to a connection between the three component virtues. One cannot have one without the other. It is especially true that devotion to family duties is essential to a ordered society. As is, I'd argue, devotion to God.
Also, one can see a connection between pietas and the Hebrew concept of shalom. Inasmuch as shalom is the condition of right relationships between God, men and nature, and inasmuch as pietas contributes to that condition by the strengthening of family and the state, pietas is an essential virtue for the establishment of shalom.