What was encaustic

"For the erection of scaffolding for the encaustic painters in the inside under roof, to Manis resident of Kollytos: 1 drachma and 3 obols". Erechtheion inscription IG 13 476.25, Expenses 7/408 – 6/ 407 BC.

"As the architect of a new house must concern himself with the whole of the structure, while the man who paints in encaustic on the walls needs to discover only what is necessary for the ornamentation, so, I judge, it is with me also." Book of Maccabees, 2, 2, 29. (2nd century BC).

"Certainly, Agrippa, in the baths that he built at Rome, painted the brick work of the hot rooms in encaustic." Pliny N.H. 36, 189.
According to Pliny, Pausias, who was taught to paint with encaustic by Pamphilus, the master of Apelles, restored with a brush the wall paintings in Thespiai painted by Polignotus. "It was he, too, who first thought of painting ceilings nor had it been the practice before his day to use this kind of decoration for arched roofs." (Pliny N.H. 35, 40). According to Varro, Pausias painted with encaustic: "Pausias and the other painters of the same school have large boxes with compartments for keeping their waxes of different colours." (Varro, De Re Rustica, 3, 17, 4). (1st century BC).

"Their figures he bids be woven in his silken robes, theirs he chases on his massy plate, or paints in encaustic on his threshold and on the ceiling of his halls". Ausonius, Epigrams, 45. (2nd century AD).
In describing the Emperor’s residence, built by Justinian in Constantinople, Procopius points out as an exception "a vault in that had not been painted with encaustic [wax] but executed with mosaic". Procopius, De Aedif. 1, 10, 15. (6th century AD).

"At the same time [768 d.C.] Nicetas the bishop of the City, restored certain structures of the episcopal church (Sancta Sofia). [...] In the reception room [...] he scraped off the images of the Saviour and the Saints made with golden mosaic and encaustic". Nicephorus, Breviarium, 86. (9th century AD).