Saint Michael Sword: Are the cathedrals really on a straight line?

Original Article ↗ Hacker News Discussion ↗

Nature of the “St Michael” Sites

  • Commenters note the seven locations are mostly monasteries, sanctuaries, or islands, not cathedrals in the technical sense (seat of a bishop).
  • Several are on pre‑Christian or obviously constrained sites (rocky tidal islands, pagan temples, defensive hills), so their exact locations were not freely chosen.
  • St Michael is an extremely common dedication: hundreds of churches in England alone, many on elevated or liminal sites and often built over earlier pagan sanctuaries.

Geometry, Projections, and “Straightness”

  • Participants stress that “straight line” is ambiguous on a globe:
    • Geodesic (shortest path on a sphere/ellipsoid).
    • Rhumb line / constant bearing (straight on Mercator).
    • Lines in other projections (Plate Carrée, equirectangular, azimuthal).
  • The alignment looks best on a Mercator map but is not a true geodesic; distances from a great‑circle line are non‑trivial.
  • Some point out Mercator’s special property: straight lines represent constant compass bearings, useful for navigation but not “natural” geography.

Coincidence, Probability, and Selection Bias

  • Many highlight the Texas sharpshooter fallacy and look‑elsewhere effect: with thousands of churches and many map projections, remarkable alignments are inevitable.
  • Rough probabilistic arguments:
    • Any 50 km‑wide band across Europe covers ~1% of the area; with ~1000 St Michael sites, dozens of such bands will contain many sites.
    • Choosing 7 from thousands dramatically increases the chance of finding an apparent line.
  • Others criticize simplistic probability estimates (e.g., GPT‑generated) as mis‑framing the question and ignoring that the line and subset were chosen post‑hoc.

Historical Feasibility and Intentionality

  • Strong skepticism that medieval builders intentionally aligned these sites using a projection they did not have (Mercator post‑dates most sites by centuries).
  • To argue intentional design, one would need:
    • Evidence of an old projection where the line is straight.
    • Historical records of such an alignment or of a “St Michael’s Sword” concept.
  • Some ask when the legend of the line first appears; cited references suggest a very recent (20th‑century) origin, not medieval.

Broader Reflections and Further Work

  • Several compare this to ley lines and other pattern‑seeking (apophenia) in landscapes and texts.
  • Suggestions for more rigorous work:
    • Build a full database of St Michael sites and search for the line that covers the most points.
    • Monte Carlo simulations of random points to quantify expected alignments.
  • Despite skepticism, many find the geography, history, and symbolism around the sites genuinely interesting.