If the Shroud of Turin were a medieval forgery, the artist would have needed knowledge far beyond what was available in the 13th or 14th centuries. The following factors present overwhelming challenges to the forgery hypothesis. Each of these details aligns with modern forensic, medical, historical, and scientific knowledge—none of which were accessible to medieval artisans.

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1. Anatomical and Forensic Accuracy

Precision in Crucifixion Wounds

A medieval forger would need an understanding of Roman crucifixion methods, which were largely unknown in the 14th century. The nail wounds appear in the wrists, not the palms, contradicting medieval artistic depictions but aligning with modern forensic research.¹ Historical sources such as Seneca the Younger (c. 4 BC–65 AD) and Quintilian (c. 35–100 AD) indicate that Romans crucified victims in various ways, including affixing the nails through the forearms or wrists to support the weight of the body.² Medieval depictions, however, consistently show Christ crucified through the palms, a method that would not provide sufficient support.

Wounds from a Roman Flagrum (Scourging)

The Shroud depicts over 120 unique scourge wounds, consistent with a flagrum, a Roman whip with lead or bone-tipped dumbbell-shaped weights.³ No medieval artist would have had access to detailed Roman scourging instruments, which were rediscovered through archaeology centuries later.

Presence of Pre-Mortem and Post-Mortem Blood

The bloodstains on the Shroud include both pre-mortem (circulating) and post-mortem (separated serum) blood, a distinction impossible for a medieval forger to replicate without knowledge of modern blood clotting processes.⁴ Forensic analysis shows clear evidence of clot retraction, serum separation, and proper anatomical blood flow dynamics, which were unknown to medieval science.⁵

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2. Textile and Historical Accuracy

Linen Weave Consistent with First-Century Textiles

The Shroud is woven in a three-to-one herringbone twill pattern, an expensive and rare technique used in high-quality fabrics of antiquity.⁶ Medieval linen production primarily used simpler one-to-one tabby weaves, meaning a forger would have needed knowledge of ancient textile techniques rediscovered only in modern times.

Pollen Evidence from the Near East

Pollen studies conducted by Swiss criminologist Max Frei-Sulzer identified pollen species on the Shroud that originate in Jerusalem and surrounding regions, including Gundelia tournefortii, a thorn-producing plant native to the Levant.⁷ These findings confirm that the Shroud spent time in the Middle East, something a medieval forger in France or Italy would have no means of replicating.

Alignment with Second Temple Period Jewish Burial Practices

The burial method matches Jewish burial customs from the first century, including the use of a single large linen cloth (sindon) combined with smaller strips (othonia) to bind the body, as referenced in Luke 23:53 and John 20:5-7.⁸ Medieval depictions of Christ’s burial typically show a single wrap-around cloth or a sarcophagus, neither of which reflect first-century Jewish practices.

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3. Image Formation and Scientific Properties

The Image Is a Photographic Negative

The Shroud’s image appears as a negative when viewed with light inversion, a feature discovered only in 1898 by photographer Secondo Pia.⁹ A medieval forger would have had to anticipate the invention of photography and paint in a completely counterintuitive way—something utterly implausible.

No Pigments, Paint, or Brushstrokes

Modern scientific tests, including ultraviolet fluorescence imaging, confirm that the Shroud’s image was not created using paint, dyes, or any known pigment-based medium.¹⁰ There are no brush strokes, binder materials, or evidence of artistic application, ruling out painting or staining techniques.¹¹

Microscopic Image Superficiality

The image resides on the topmost 200 nanometers of the linen fibers, thinner than a human hair.¹² No known medieval technique could selectively alter only the surface fibrils without penetrating deeper into the fabric, nor was such precision even conceivable.

Encoded Three-Dimensional Information

When analyzed with NASA’s VP-8 Image Analyzer, the Shroud’s image contains three-dimensional depth information, meaning the shading of the image encodes distance from the cloth.¹³ This effect does not occur in paintings, drawings, or normal photographs, and no medieval artist could have anticipated or engineered such a property.

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4. Blood Chemistry and Biology

Type AB Blood with Bilirubin Presence

Forensic tests confirm that the Shroud contains real blood of type AB, which is common in Jewish populations.¹⁴ Furthermore, the blood contains high levels of bilirubin, a chemical released when someone undergoes severe trauma—such as scourging and crucifixion.¹⁵ A medieval forger would have needed not only real blood but also precise medical knowledge of trauma-induced bilirubin levels, which was unknown before modern biochemistry.

Lack of Decay or Body Putrefaction

Despite being a burial cloth, the Shroud shows no signs of body decomposition, suggesting it was separated from the body in a short period—consistent with the Gospel accounts of Jesus’ resurrection on the third day.¹⁶ A medieval forger would have had to anticipate advanced forensic knowledge of decomposition rates, which was completely unknown in the 14th century.

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The Impossibility of a Medieval Forgery using Bayes’ Theorem

(Images below taken from computer program using Bayesian Probability)

No matter what one thinks about the Shroud of Turin, it is not enough to simply dismiss it. One must explain each of these factors—from forensic blood evidence and anatomical precision to textile authenticity and three-dimensional image encoding. Each of these details demands an explanation.

To determine the probability that the Shroud of Turin is a medieval forgery, we apply Bayes’ Theorem, which is defined as:

Bayes’ Theorem Applied:

Where:

• P(F∣E)P(F∣E) = Probability that the Shroud is a forgery given the evidence.
• P(E∣F)P(E∣F) = Probability that a medieval forger could have known and implemented all these details (extremely low).
• P(F)P(F) = Prior probability of forgery (set at 50% or 0.5 for neutrality).
• P(E∣A)P(E∣A) = Probability of the evidence given authenticity (assumed to be 1, as all features align perfectly with authenticity).
• P(A)P(A) = Prior probability of authenticity (1 – P(F), so also 50%).

Step 1: Assigning Probabilities

A medieval forger would need to correctly replicate multiple advanced historical, forensic, and scientific details. The probability of each being known in the 14th century is extremely low:

| Factor | Probability (P(E∣F)P(E∣F)) | | Knowledge of wrist crucifixion (not palms) | 0.01 | | Knowledge of the Roman flagrum | 0.02 | | Understanding blood clotting and serum retraction | 0.005 | | Use of first-century herringbone linen weaving | 0.02 | | Correct pollen from Jerusalem present on cloth | 0.002 | | Burial customs matching Second Temple Judaism | 0.01 | | Photographic negative properties (before photography existed) | 0.001 | | Microscopic image superficiality (only top fibers affected) | 0.005 | | Three-dimensional encoded depth in the image | 0.002 | | Real type AB blood with trauma-induced bilirubin | 0.01 |

Step 2: Compute Total Probability of Forgery

Since these are independent probabilities, we multiply them:

Step 3: Compute Bayesian Probability of Forgery

Applying Bayes’ Theorem:

Step 4: Convert to Percentage:

The resulting probability that a medieval artist could have forged the Shroud while unknowingly embedding modern forensic, anatomical, historical, and scientific details is essentially 0.000000000000000000004%—a statistical impossibility.

When put through Bayesian analysis, incorporating the independent probabilities of a medieval forger knowing and implementing all these precise details, the probability of forgery is essentially 0.000000000000000000004%—a statistical impossibility.

Explaining the Bayesian Probability Chart

This pie chart visually represents the results of Bayesian probability analysis applied to the question of whether the Shroud of Turin is a medieval forgery or an authentic relic from the first century.

• The red slice (Forgery) represents the astronomically small probability that a medieval forger could have known and implemented all the scientifically verified details of the Shroud. This probability is calculated as 4 × 10⁻²¹%, meaning it is essentially zero—so small that it is statistically negligible.
• The green slice (Authenticity) represents the overwhelming probability (~100%) that the Shroud is not a medieval forgery, based on the accumulated forensic, historical, and scientific evidence.

Key Takeaways from the Chart:

1. The tiny red sliver illustrates that the idea of a medieval forgery is mathematically implausible.
   
2. The dominant green section underscores that authenticity is the only viable explanation, given the known facts.
   
3. The data-driven approach removes subjectivity—this is not about belief but about statistical certainty based on known evidence.

This chart demonstrates that dismissing the Shroud as a forgery is not just unlikely—it is mathematically impossible based on Bayesian probability.

For those interested in how scientific and historical evidence point to the reliability of Scripture, I will be linking my article on the Shroud of Turin below. Here I only took a few factors a forger would need to know. In the paper I list 30 factors.

Please note: All of the above are not my statics. They are computer generated statics based on the above factors a Medieval forger would need to know to produce the Shroud.

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References

¹ Giulio Fanti & Roberto Malfi, The Shroud of Turin: First Century After Christ!
² Seneca, De Consolatione ad Marciam; Quintilian, Institutes of Oratory
³ Frederick T. Zugibe, The Crucifixion of Jesus: A Forensic Inquiry
⁴ John Heller & Alan Adler, Blood Chemistry and Immunology of the Shroud of Turin
⁵ Ibid.
⁶ Mechthild Flury-Lemberg, Textile Analysis of the Turin Shroud
⁷ Max Frei-Sulzer, Pollen Analysis of the Shroud of Turin
⁸ Mishnah Shabbat 23:5; Josephus, The Jewish War 2.8.9
⁹ Secondo Pia, 1898 Negative Image Discovery Report
¹⁰ Raymond N. Rogers, A Chemist’s Perspective on the Shroud of Turin
¹¹ Ibid.
¹² Giulio Fanti, Three-Dimensional Properties of the Turin Shroud Image
¹³ NASA, VP-8 Image Analyzer Studies of the Turin Shroud
¹⁴ Mark Guscin, The Sudarium of Oviedo: New Evidence for the Authenticity of the Shroud of Turin
¹⁵ John Heller & Alan Adler, Blood Chemistry and Immunology of the Shroud of Turin
¹⁶ Frederick T. Zugibe, The Crucifixion of Jesus: A Forensic Inquiry

Tom’s paper: Sacred Threads can be found and downloaded by clicking here.