Aspects of medieval culture are often sufficiently different from modern culture to seem decidedly weird. Today's example: the "bride of Christ" motif.
It was common, in the Middle Ages, to describe nuns as brides of Christ. Consecrated virgins took Christ as their husband in lieu of an earthly husband. Much is made of this in any number of sources: one can find treatises discussing Jesus' superiority as a husband to any mere man and admonitions about how nuns must behave themselves lest they shame their "husband."
What becomes odd about this, to a modern reader, is how very literal much of the discussion of the motif is. Nuns are not merely metaphorical brides, but actual brides. The liturgy for consecrating a nun, for example, may contain direct references to the theme. The signature item of apparel for a nun was not so much her habit as her veil, an attribute of brides. When you look at the lives of individual holy women, you can find even more direct references: the ancient St. Katherine of Alexandria, according to her vita, received a ring; St. Catherine of Siena is among several holy women actually living in the Middle Ages who had similar visions of a ring and wedding ceremony. Special relationships with Christ, often accompanied by suggestive ecstasies, abound among female mystics. I have also found a text referring to Katherine of Alexandria's entrance into the celestial bedchamber. Medieval people were not just speaking poetically with this "bride of Christ" stuff; for many of them it appears to have been spiritual reality.
And where this gets even weirder...maybe even slightly disturbing...is when you reflect on the fact that Jesus was supposed to be married to all these nuns and saints at the same time. My current research has brought that home to me, as the texts shift back and forth between talking about a nun's individual relationship to Christ, as his bride, and talking about the nuns' spiritual endeavor as a collective. Such shifts seem a bit awkward, juxtaposing the spiritual reality of being a bride of Christ with the mundane reality of being a nun in a monastery together with many other nuns. How special could a nun feel about being Christ's bride when Sister Snoresalot, or Sister Condescending, in the next cell was also Christ's bride? The theme was widely used, for all sorts of purposes, and yet no one in the Middle Ages seems to have considered these implications.