The biblcal passage that sheds most light on this question I believe is 1 Peter 3:18-20.
For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the spirit: By which also he went and preached unto the spirits in prison; Which sometime were disobedient, when once the long-suffering of God waited in the days of Noah, while the ark was a prepareing, wherein few, that is, eight souls were saved by water.
Also 1 Timothy 3:16.
And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the spirit, <B>seen of angels</B>, preached unto the Gentiles, believed on in the world, received up into glory.
Colossians 2:15.
And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it.
The Apostles' Creed, composed in the early Christian era, reads "He descended into Hell and on the third day rose again"
The interpretation I believe for these passages is that after Jesus died he went to proclaim his victory to the fallen angels. The same angels Peter talks about in 2 Peter 2:4.
For God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment.
And also the angels Jude talks about in Jude 6.
And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.
Jesus wanted to let these fallen angels know his victory had been completed at the cross, and thus their judgment had been sealed. This event was so monumentous in history, his victory so complete, he wanted them to know that forever more He and he alone is Lord of all.