One of the earliest renditions of a Chamorro comes from a manuscript allegedly written sometime in the 1590's. The manuscript is contemporarily referred to as the "Boxer Codex." Just Google it or go to Wikipedia and you will find out more about Boxer Codex. The physical and digital copy of the manuscript is housed at Indiana University.
One of the interesting things of the many mysteries of this manuscript is that although the book cover is labeled "La Del Ladrones," there is only one picture of a Chamorro, which by the way happens to be the first picture in the book. The picture on the right (page 2) following the Chamorro is misleading to the point that one would think that the Chamorro people in the 16th Century had weaponry of bows and arrows, when there has been no archaeological or historical evidence to support it. It is believed that the man with the bow and arrows comes from either a Filipino or other Far Eastern tribe.