Next to the larger, newer, and more stately Metropolis Cathedral in the heart of Athens is an inconspicuous little building that shouldn’t be overlooked.

Measuring just 25 feet by 40 feet and shadowed by the surrounding buildings, many tourists mistake the Church of St. Eleftherios as one of the many stabilized ruins standing in the ancient city.

But upon closer inspection, this odd church has a marvelously mashed-up history that dates back nearly a millennia and still remains largely unchanged since it’s construction.

Commonly called the “Little” Metropolis Church, purported dates of it’s creation vary widely with scholars arguing anywhere from the 8th century to the 15th. The reason for the confusion is due to the repurposed use of building materials, mostly marble blocks from non-Christian temples, that were cobbled together to build the church.

Assembled from older pagan temples from the area made sense at the time. Not only was it cheaper and more convenient, but it also removed the old heathen religious artifacts from public record. The patching together of previously used building material, called “spolia” is not uncommon for the ancient world, and the process of “baptizing” these pagan objects was simple: just carve a cross on it.

This practice of neutralization, known as “sphragis,” covers the Little Metropolis Church. Almost all of it’s blocks with images have little crosses carved in them despite depicting ancient Greek and Roman gods.