The contribution is based on the assumption that ethnography should incorporate the temporal dimension of the processes being studied. I draw on my long-term ethnographic studies on literacy practices in school and community contexts in the indigenous (Nahua) region of Tlaxcala to illustrate ways in which we can historicize ethnographic analysis. From this perspective, cultures of schooling can not be seen as universal and unchanging, but rather as forged locally through the appropriation and construction of the resources needed to do the work of teaching and learning. The methodological approach involves ethnographic fieldwork, as well as incorporation of documentary data and oral testimonies, to gain a sense of the changing nature of classroom practices and gauge the consequences of past reforms. In this paper, I will discuss the problems of keeping the historical dimension in mind while doing fieldwork and writing rich ethnographic descriptions of everyday life in schools