Complex sentence: Stelae with the earliest known Long Count dates come from this general area some of the oldest unargued calendric inscriptions in this format are from the early Zapotec phases in the Oaxacan highland valleys at sites such as Monte Albán, dating from the mid 1st-millennium BCE.
Split into simpler sentences: Stelae with the earliest known Long Count dates come from this general area. Some of the oldest calendric inscriptions are from early strata of Zapotec in the Oaxacan highlands at sites such as Monte Albán, dating from mid 1st-millennium BCE.