If you google 'cugullo' you won't get many results. I got 470.
There are a lot more and more relevant Google Search results than merely these 470.
It is often best to refine an initial Google search and make it more targeted based on the first search result. For example google for
Igúzquiza Cogullo or
Cogullo Navarra. Internet search machines are dumb and one needs to be more clever and more imaginative than they are. Even a simple change such as googling for
Iguzquiza Cogullo instead of
Igúzquiza Cogullo will provide a couple of hundred more results. With all this, one can create new combinations, perhaps try
Cogullo encomienda.
Or try searches with various known (or even just plausible) spellings of the name, such as
Cucuillo and
Goguyllo but be attentive when you read, for example, that [translated from Spanish]
Arturo Campión confounds Cocullo and Cogullo. According to him, other documents clearly refer to Guguyllo. A character of the Navarreria, cited in the poem of Aneliers, is called Simeno de Cucuyllo. Campión derives Cucuyllo-Guguyllo-Euguillo-Eugillor or Euguylloz. This claim does not appear to be very convincing to us.
Post on the forum when such preliminary searches do not bring results. When it comes to historical accuracy and information value, do not put too much faith in Camino guidebooks and readers who copy a few lines from them or in information provided by tourism offices.
Brierley's chosen orthography of Cugullo for this location where there once was one of the many small medieval hostels for poor people and pilgrims is unfortunate. Not surprisingly, it got picked up by his readers. See
Camino de Cogullo for a list of post-medieval spellings for the same location, among them
Cugullo.
Cogullo is no more. It has ceased to be for at least 700 years. It got abandoned in the Middle Ages and lives on only as a toponym. See for example José Javier Uranga,
Notas sober topónimos navarros medievales.