Gordion Megaron II

The world's oldest extant mosaic floor was discovered during the excavations carried out in 1956-7  in the building called Megaron II in the city of Gordion . It dates back to the 9th century BC. This was probably the site of Phrygian mother goddess Matar temple.

See:

1. Thompson, Elizabeth T.. “Documentation and Evaluation oIf the Conditions of the 9th Century B.C.E. Mosaic, from Gordion, Turkey and Recommendations for its Conservation and Treatment.” 201).
2. Wohlgemuth, Kevin Adam. “Revisiting Gordion’s Pebble Mosaic Pavement: Evaluating Re-Backing Techniques and Investigating Alkali-Silica Reaction.” 2014.
3. https://www.penn.museum/sites/gordion/history/iron-age-gordion/