7 Deer, an Equinox date in San Bartolo Geraldine A. Patrick Encina January 21, 2023 The San Bartolo Las Pinturas Sub-V phase architectural complex consists of a radial structure, a miniature ballcourt, and an elongated platform referred to as structure Ixbalamque. Together they form an E-Group with its characteristic orientation to the rising sun at equinox. This E-Group was built sequentially over several centuries. Stuart et al. (2022) estimate that: it is probable that the Sub-VII and Sub-VI phases of the E-group were built in the fourth or third centuries BCE, with its long eastern structure rebuilt shortly after initial construction, and, when together with the dates from the Sub-1A phase, that all of the Sub-V texts were likely painted and incised between 300 and 200 BCE, with greatest probability being the latter half of the third century BCE. E-Groups were first described in the context of Uaxactun for several dozen sites within a 100-km radius of Uaxactun in Calakmul, Nakum, Naactun, Yaxha, Uxul, Benque Viejo, Ixkun, Rio Bec, La Muñeca, and Cahal Pichik, and many archaeologists have discussed the function of their configuration (Karl Ruppert 1940, Rathje 1973, Aveni and Hartung 1989, Laporte and Fialko 1990). Most agree that the intended astronomical function of the E-Group was to mark the arrival of equinoxes and solstices, even though at some sites there was less effort to adhere to the architectural requirements that would ensure such function (Aveni 2001:292). Just like sites around Uaxactun fall in the transition period between Pre-Classic and Early Classic, the San Bartolo Las Pinturas Sub-V phase E-Group is a Pre- Classic complex. In this sense, it is feasible to consider that the ritual function of the E-Group was linked to the astronomical observation of equinoxes and solstices. Archaeoastronomers like Ivan Sprajc have always argued that when it comes to verifying that E-Groups emphasize the astronomical event of a rising sun on