Serdica (Sardiki) is one of the old names of the city of Sofia. It was named under the Celtic (or Thracian) tribe Serdi that had a settlement here from the 5th or 4th century. For a short time (4th c.) it was under the rule of Philip II of Macedon and his son Alexander the Great. In 29 BC it was conquered by the Romans (during the reign of Emperor Trajan – Ulpia Serdica). From that time the city developed as an important center of the Roman provinces of Moesia and later of Dacia Mediterranea. Many public buildings were erected during this period. It was one of the first cities where the Christianity was recognized as an official religion (Emperor Galerius).
In different periods a lot of remains of the old city of Serdica were unearthed (mainly in center of the nowadays city) by archaeologists and are displayed for the audience. Many artifacts from the excavations are shown in the Archaeological Museum and in the National History Museum. Recently during the construction works in the center of the city were discovered parts of the main streets with public buildings, Amphitheatre, Stadium etc. In the subway in front of the Presidency the remains the East Gate of the old city with two pentagonal towers. In the courtyard of the Presidency can be seen the complex of remains with the so called Rotunda (now the church of St. George – frescoes from 12 – 14th c.).
In the basement of one of the best hotels in Sofia – Arena di Serdica – a part of the Serdica Amphitheatre can be seen.