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Evidence Matters: The Case of the "Lying Monk"

Our beliefs can depend heavily on the sources and presentation of evidence.

Key points

  • Evidence in the forensic world, and in daily life, may be accepted with limited consideration of its source.
  • The sources of evidence, and the language in which it is presented, can be critical for accurate analysis.
  • Historical cases such as that of Marcos de Niza can demonstrate these issues clearly.
Matthew Sharps
Source: Matthew Sharps

Criminal courts typically impose strict rules of evidence. For example, eyewitness evidence is usually scrupulously separated from hearsay evidence.

However, such rules do not apply in other important contexts, including the court of public opinion. Evidence about what we believe, as compared to verifiable reality, may appear to have gone through the childhood game of Telephone; as the kids whisper to each other, the final version of the information may bear no resemblance to whatever they started with.

Language may contribute strongly to such effects (Sharps, 2022). Consider the title of this post of the Forensic View, "Evidence Matters." In using those words, did I mean that the post was going to be about matters pertaining to evidence, or did I mean that evidence matters, that it is important?


In this case, the ambiguity of the statement reads properly both ways. Yes, the post is about evidentiary matters, and yes, evidence matters enormously. So, here, both interpretations are correct.

But what if a similar ambiguity in language could be interpreted in different, potentially opposing ways? And what if we can't know that the information we receive really reflects the source of that information at its point of origin (the Telephone game again)? Under these conditions, fairly typical of the real world, what results would we expect?

We'd probably wind up with something like the fate of the massively maligned monk, Marcos de Niza.

Fray Marcos was a Franciscan friar living, at the time of the relevant events, in what is now Mexico. Hernan Cortez's Spanish conquistadors had recently extracted an incredible quantity of gold from the Aztec people, following which they had inadvertently dropped most of it into the lake beneath Mexico City, where it presumably still resides.

However, this disaster was only the beginning. The conquistadors had caught serious gold fever, and their Viceroy sent Marcos de Niza on a fact- and gold-finding mission into what is now the Southwestern United States, where, according to much scholarly opinion, he appears to have become clinically insane.

Scholars tell us that Marcos claimed to have seen that the Gulf of California coastline veers away to the West (at approximately the point at which it actually does) when he couldn't possibly have gotten there within the time limits of his trip. He is supposed to have seen weird and impossible animals at the Cities of Cibola, his expeditionary goal. He supposedly described Cibola as filled with gold, the buildings encrusted with emeralds, and the whole place "grander" than Mexico City of his day.

None of this was true, of course, and many scholars seem divided on the question of whether Marcos was suffering from psychosis or simply a "Lying Monk." Scholarly debate continues.

But the problem is that none of this really reflects what Marcos actually said.

The "Cities of Cibola," a term with legendary significance, were small villages in the area of Zuni Pueblo in New Mexico today. They possessed essentially no gold, not a single emerald, and they were singularly devoid of weird animals. What the inhabitants possessed, in the area surrounding Hawikuh (today a ruin of the town Marcos reported he saw), were some turquoises which they wore or set into the doorways of their multi-storied dwellings, together with a tremendous amount of relatively flat dirt with corn growing in it.

Now, suppose you were Marcos. You've seen Hawikuh in its heyday, with all that flat dirt. Would you really have taken a second trip to the place, accompanied by several hundred homicidal conquistadors, knowing that they expected sacks of gold and piles of emeralds? When all that these truly dangerous men would find was some corn and little green rocks?

Yet Marcos did exactly that. Apparently, on arrival at Hawikuh, the conquistadors' curses were epic, and sufficiently homicidal that Marcos had to beat it back to Mexico with all speed. In his writings, he appears to have understood that they were lethally upset with him, but you get the impression that he really didn't understand why.

How is this possible? Does anything in this story actually make any sense?

Well, Marcos did say that he "saw" how the coastline of the Gulf of California went West, and scholars have gleefully pointed out that he would have had to sprint to get there in the time reported. However, this may have had less to do with the "Lying Monk's" fleetness of foot than it did with language (Hartmann, 2014). I personally have "seen" that psychological principles apply to the forensic realm. I never had to travel any place to "see" this fact, and neither did Marcos when he "saw" a fact of coastal geography explained by his Native informants. No lies or supersonic speeds are necessarily required to explain this statement.

It may be essentially the same with Cibola's being "grander" than Mexico City. The Cibolan villages had nothing like the architecture of Mexico City, but the area occupied by those villages was quite large. Marcos may have been comparing the spread of Mexico City at that time with the area occupied by the villages (Hartmann, 2014).

The ambiguities of language again.

Gold? Marcos never actually claimed he saw any, but his barber said he did, spreading the rumor after a supposed conversation with Marcos during a shave.

Emeralds? There were turquoises decorating the doorways of Cibola, which Marcos described correctly; but writings of the time demonstrate a frequent conflation of the words "emerald" and "jade" with the turquoises the Cibolans actually had. There were little green rocks in the walls, just as Marcos said.

Weird animals? There are none in Marcos' actual writings; they turned up in a letter by somebody else.

The fabulous elements of Marcos' story were largely attributed to him by others, in ways that are still ubiquitously observed. The ultimate lesson of Marcos' saga may be that today, with a constant bombardment of conflicting claims in media and on the Internet, the psychological study of evidence may be increasingly important.


Harmann, W.K. (2014). Searching for Golden Empires: Epic Cultural Collisions in Sixteenth-Century America. Tucson: University of Arizona Press.

Sharps, M.J. (2022). Processing Under Pressure: Stress, Memory, and Decision-Making in Law Enforcement (3rd ed.). Park City, Utah: Blue 360 Media.

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