Modern San Mateo Ixtatán is superimposed on pre-Columbian mounds and plazas. The structure immediately underlying the modern town dates from the Late Classic period ( A . D . 600-900). A major "temple" complex and platform/courtyard lie below the city, which sits astride a rich salt deposit. Chuj salt was traded north through Tzeltal and Tzotzil regions of Mexico. The salt dome is accessible through a series of four wells. During the period of civil strife called the violencia (ca. 1979-1982), Guatemalan troops cut forests along the roadways; the deforestation lowered the water table to such a degree that only a single salt well remains in full production. A large temple mound overlooks the main well.
In the pre-Hispanic period, San Sebastián Coatán was a focal point of trade and ritual pilgrimages centering on its natural features, particularly its springs. According to local belief, Saint Sebastian and Saint Michael were walking the hills of the area, looking for a place to settle and to form towns for their followers. Saint Sebastian found a mountain ledge that he liked and called to Saint Michael, in Chuj, "Kotanh!" (come here!). But Saint Michael had also found a place that he liked; so he replied in Akateko/Q'anjob'al, "Aa Katan!" (oh, come here!). Eventually, each saint settled, with his following, on opposite sides of a ravine. The people in San Miguel Acatán share this traditional history.
The place names "Coatán" and "Acatán" are Nahuatl terms. "Coatán" (from coa: , "snake," and tlan/tan , "place") means "place of the snakes." "Acatán" (from a:ca, "reed," and tlan/tan, "place") would mean "reed place." Although there are reeds in the Acatán area, residents of San Sebastián deny the presence at any time in their history of large numbers of snakes. The Ixil, however, neighbors south and east of the Q'anjob'alan group, conserve in their oral histories an account of how San Sebastián came to be infested with snakes: a woman who had been converted into a half-human, half-snake, because of her laziness, was dropped on the plaza from a great height, and she shattered into hundreds of pieces, each of which become a serpent.
Nentón is a new settlement, dating from the early 1900s, when coffee was developed as an export crop.
In most of Guatemala, townships have characteristic trade "garb" for both men and women, but men tend to reserve this traditional wear for feast days. In San Mateo, the woman's trade garment is a cotton broadcloth overblouse (Chuj: nip ; Spanish from Nahuatl: huipil ) elaborately embroidered in red, yellow, green, and black. Before the 1960s the design was one of concentric multicolored circles (the colors arranged roughly as on the coral snake), with birds and flowers adorning the bottom edge, below the outer circle. The overblouse was long, reaching nearly to the knees, and was typically worn over a wrapped skirt. Women wore their hair braided and wrapped with brightly colored woven ribbons. The men wore and still wear cotton pants and shirts, unembroidered, and a wool short-sleeved tunic, (Chuj: lopil ; Spanish: capixay). The tunic is lightly embroidered at the neck and arms. The arms are not closed, but open at the bottom, and the side seam is left open for several inches below the arms to allow freedom of movement while working and to facilitate pulling the arms inside while resting. In the 1960s the women's overblouse design changed. The concentric rings were rearranged as stars, three in front (one over each breast, one over the stomach), three symmetrically placed in the back. The blouse got shorter and was often worn tucked into the skirt. Since the early 1980s, many women have reserved their overblouses for festival use, and use cotton blouses, sewn in a short, puff-sleeve, square-neck pattern, for daily wear. A short "mini"-length apron, with two zippered pockets has been added. Married women now cover their braids on formal occasions with square scarves of polished cotton. The men's trade garb has remained relatively stable, although the shirt and pants may now be manufactured items. Men in San Sebastian and Nentón dress in basically the same manner, although they tend to wear the wool tunic less as the weather is warmer than in San Mateo. Women in San Sebastián wear a white cotton (often polished) overblouse with internal paisley patterning or lacelike netting, the neckline adorned with concentric rings of colored rickrack and white lace. When traveling, they often wear an overblouse inverted over their heads, as a headcloth. The headcloth overblouse and the one worn on the body can be interchanged, if one gets worn or dirty. The pattern of the women's overblouse in San Sebastián is shared with the Jakaltek, Akatek, and Q'anjob'alan towns of the region. Most women of Nentón wear occidental clothing, though some conserve the wrapped cloth shirt.