Cardinal virtues
Augustine of Hippo, discussing the morals of the church, described them:
The "cardinal" virtues are not the same as the three theological virtues: Faith, Hope and Charity (Love), named in 1 Corinthians 13. 
"And now these three remain: faith, hope and love. But the greatest of these is love."
Because of this reference, a group of seven attributes is sometimes listed by adding the four cardinal virtues (prudence, temperance, fortitude, justice) and three theological virtues (faith, hope, charity).
Together, they comprise what is known as the seven virtues. While the first four date back to Greek philosophers and were applicable to all people seeking to live moral lives, the "theological virtues" appear to be specific to Christians as written by Paul in The New Testament.
Fortitude (Botticelli)
Upon first glance, the eye is pulled to the most illuminated point of the painting: the face of Fortitude. Her gaze is turned down and away from the observer and because of this, her expression is perceived as passive and uninterested. This was a characteristic feature of Botticelli's female figures. It is a fascinating contrast to the theme of the title because if she represents strength, why does she express otherwise? This work, which is one of seven virtues, was intended to be placed high upon a wall. This would be higher than the eye level of the viewer, therefore requiring them to look upward. In the line-up of all seven paintings of the virtues, Fortitude is the first. Perhaps her gaze is intended to literally and figuratively watch over the other virtues as well as the viewers. Without strength, one can never fathom taking on the other six virtues.