The story of Christmas began when three wise men saw something strange in the sky and decided to investigate.

Anyone who's seen a UFO can easily relate to what those wise men might have been thinking, and that's what makes the images in these paintings so compelling.

Many unusual aerial objects depicted in paintings between the 14th to the early 18th century look, at first glance, like modern-day UFO sightings.

It's easy to wonder why artists of those long-ago centuries seemed obsessed with including these curious objects in scenes surrounding the stories of the birth and death of Jesus Christ.

The first example here is a wall mural, or fresco, from 1350, "The Crucifixion," artist unknown, in the Visoki Decani Monestary in Kosovo, Yugoslavia. Two odd-looking objects with "pilots" can be seen in the sky on both sides of Jesus.

"As odd as the details in the upper left and right sections of the Kosovo fresco may seem to modern eyes, they, in fact, refer to something readily familiar: the sun and the moon," according to Dennis Geronimus, associate professor of Italian Renaissance art and chair of the Department of Art History at New York University.

"The strangeness, to our sensibilities, no doubt lies in the fact that the two celestial bodies are personified by two crouching figures that are shown as inhabiting them: producing a kind of 'man in the moon' effect," Geronimus told HuffPost in an email.

He added that the apparent simultaneous presence of both the sun and moon, "alludes to mentions in several of the Gospels of the sky growing dark in daytime during Christ's crucifixion."

Our next painting, from 1486, is "The Annunciation with Saint Emidius," by Carlo Crivelli, that resides at the National Gallery in London. It shows a circular object shooting a thin beam of light down to the Virgin Mary.

"The golden beam descending from a cloud bank through an opening in Mary's bedroom wall, and reaching its destination at the Virgin's head, carries along its path the Holy Spirit," said Geronimus. "Characteristically, here it assumes the form of a white dove and symbolizes the incarnation.  

"The Virgin Mary is shown as being infused -- or, to put it literally, impregnated -- with the Holy Spirit, a miraculous event that will lead to the birth of Christ."

The following image is a close-up of that circular cloud bank.

Computer scientist Jacques Vallee agrees with Geronimus' take on these works of art. But he wonders why this form of symbolism seems to crop up in so many works of art from these years.

"It's certainly true that these paintings do not represent actual sightings by the artist or contemporary events of the scene," Vallee told HuffPost. Vallee and his co-author, Chris Aubeck, are about to publish an extensive update to their 2010 book, "Wonders in the Sky," which looks at reports of strange aerial objects reported by many people -- including scientists -- in pre-20th century accounts, beginning in 1879 and moving backward in time to biblical sightings.

"The value of it, scientifically, is that now we can anchor the beginning of the UFO phenomenon into real, documented history," Vallee said.

"You cannot simply say that, because somebody saw something round in the sky in medieval times, it's the same phenomenon that people see today. We are not making that statement. We're simply describing what people saw and the phenomena associated with it as a contribution to the overall study of the history of the phenomenon."

Vallee (see image below) was a principal speaker in 1978 at the only major United Nations UFO presentation in history, where he urged serious, international, unbiased research, focusing on those UFO reports considered truly unidentified.