In 1953 the first incision was made on the hill of Kasta by local residents, because of traces of stonework on the top of the hill. In 1964 the official excavation began, led by Dimitris Lazaridis, and a four-sided structure was discovered, with side length 10 meters and height 5 meters, while based on scattered architectural parts found, by K. Peristeri and M. Lefantzis, that the Lion of Amphipolis was once at the top of the tomb, on the four-sided structure. The excavations continued in an area of 20 acres on the hill and 70 graves were found. In 2012, efforts were begun by archaeologist Katerina Peristeri to locate the boundaries of the tomb, and its enclosure was found 12 metres below the surface where the excavations were taking place.
The burial enclosure is 497 metres long and dates back to around 325 - 300 BC during the reign of Alexander the Great. It is made of marble from Thassos and according to the estimate of the excavation manager, it is the work of Dinocrates, of the period 325-300 BC. From the excavation in the tomb three successive chambers have come to light that communicate with each other with doors, while in the third chamber there is a smaller door that seems to lead to a fourth chamber, but it is not certain that this is the last or funerary chamber. Excavations are ongoing and it is not yet certain to whom this particular tomb belongs. Since the release of the first findings, many different opinions have emerged as to who or what the deceased is, and whether it is one or more. According to the theory of Andrew Chag, author of the book "The search for the tomb of Alexander the Great", the Caryatids found in the door of the second chamber represent priestesses of Dionysus, with whom the mother of Alexander, Olympiad had a relationship. Some archaeologists, who are not related to the excavation, formulate the view that only the core of the tomb is Hellenistic, but the hypothesis is rejected by the person in charge of the excavation stressing that all the data show that " it dates back to the last quarter of the 4th century BC. century, that is after the death of Alexander the Great until 325- 300 BC ".
In September 2015 and according to the presentation of the results of the excavation team at the Kasta Tomb as to the investigations carried out from 2012 to 2014, it was announced that the monument was built to order by Alexander the Great for Hephaestion, with the manufacturer being Dinocrates.