I don't know how many churches there are in Karpathos. No one knows for certain. There are the village churches — the big ones, with the bell tower, where mass is celebrated every Sunday — and then there are the votive chapels, the small white ones, leaning against a rock wall or built on the edge of a cliff. Every well-off family built one, out of devotion or as a vow. Some date back to the Byzantine era.
The oldest one with certain evidence is the church of Agios Konstantinos, near Aperi, which preserves architectural elements from the 11th century. But the Byzantine churches are scattered everywhere — in the fields, on the hills, hidden among the scrub. Some have been restored, many are abandoned with the door shut and the icons still inside.
In Karpathos the churches aren't touristy. They're in use. If you step in while someone is praying, you know it right away.
Karpathian tradition holds that the patron saint of every chapel is celebrated every year, even if the chapel is in the middle of nowhere. The family who looks after it organises a small ceremony, brings food and wine, lights the candles. It's one of those rites that seem marginal but that have held a community's fabric together for centuries.