Objection 1. It would seem that the virgin's aureole is the greatest of all. For it is said of virgins (Apocalypse 14:4) that they "follow the Lamb whithersoever He goeth," and (Apocalypse 14:3) that "no" other "man could say the canticle" which the virgins sang. Therefore virgins have the most excellent aureole.
Objection 2. Further, Cyprian (De Habit. Virg.) says of virgins that they are "the more illustrious portion of Christ's flock." Therefore the greater aureole is due to them.
Objection 3. Again, it would seem that the martyr's aureole is the greatest. For Aymo, commenting on Apocalypse 14:3, "No man could say the hymn," says that "virgins do not all take precedence of married folk; but only those who in addition to the observance of virginity are by the tortures of their passion on a par with married persons who have suffered martyrdom." Therefore martyrdom gives virginity its precedence over other states: and consequently a greater aureole is due to virginity.
Objection 4. Again, it would seem that the greatest aureole is due to doctors. Because the Church militant is modelled after the Church triumphant. Now in the Church militant the greatest honor is due to doctors (1 Timothy 5:17): "Let the priests that rule well be esteemed worthy of double honor, especially they who labor in the word and doctrine." Therefore a greater aureole is due to them in the Church triumphant.
I answer that, Precedence of one aureole over another may be considered from two standpoints. First, from the point of view of the conflicts, that aureole being considered greater which is due to the more strenuous battle. Looking at it thus the martyr's aureole takes precedence of the others in one way, and the virgin's in another. For the martyr's battle is more strenuous in itself, and more intensely painful; while the conflict with the flesh is fraught with greater danger, inasmuch as it is more lasting and threatens us at closer quarters. Secondly, from the point of view of the things about which the battle is fought: and thus the doctor's aureole takes precedence of all others, since this conflict is about intelligible goods. while the other conflicts are about sensible passions. Nevertheless, the precedence that is considered in view of the conflict is more essential to the aureole; since the aureole, according to its proper character, regards the victory and the battle, and the difficulty of fighting which is viewed from the standpoint of the battle is of greater importance than that which is considered from our standpoint through the conflict being at closer quarters. Therefore the martyr's aureole is simply the greatest of all: for which reason a gloss on Matthew 5:10, says that "all the other beatitudes are perfected in the eighth, which refers to the martyrs," namely, "Blessed are they that suffer persecution." For this reason, too, the Church in enumerating the saints together places the martyrs before the doctors and virgins. Yet nothing hinders the other aureoles from being more excellent in some particular way. And this suffices for the Replies to the Objections.
Source: Summa Theologica (New Advent)