A Puuc Maya city south of Uxmal that flourished briefly but intensely in the Terminal Classic, reaching a population of roughly 10,000 (with 5,000-7,000 more in the surrounding area) around 900 CE; its ruined Grand Palace is a landmark of Puuc monumental architecture.
Sayil's primary phase of occupation ran from about 800 to 950 CE (Late to Terminal Classic), with rapid growth to its greatest extent c. 900 followed by abandonment of the monumental core and a brief continued residential reoccupation.
Regional archaeological survey naming Sayil directly alongside its immediate Puuc neighbors; verified on Open Library. (A dedicated Sabloff/Tourtellot 'Sayil' monograph exists in the literature but its exact title could not be verified on Open Library, so it was not used.)