Serdi Authority in Tribe from to .
The Serdi were a Celtic tribe inhabiting Thrace. They were located around Serdika, now Sofia in Bulgaria, which reflects their ethnonym.

They would have established themselves in this area during the Celtic migrations at the end of the 4th century BC, though there is no evidence for their existence before the 1st century BC. Serdi are among traditional tribal names reported into the Roman era. They were gradually Thracianized over the centuries but retained their Celtic character in material culture up to a late date.

The Serdi struck coins imitating various Macedonian issues. Like other Celtic coinage, the imitations were not meant to be counterfeits but were used as local coinage.
Serdi
(1) Serdi
/Files/Images/Coinsite/CoinDB/Strymon_3.jpg
An AE unit struck 168-31 BC in Thrace
Obverse: Head of rivergod Strymon right

Reverse: Wide trident

Diameter: 22 mm
Die Orientation: 0 H
Weight: 8.37 g

Celtic imitation of Macedonian issue from 185-168 BC. Overstrike of Thessalonica, 187-31 BC, head of Dionysos with ivy wreath right, goat standing right, ΘEΣΣA_ΛO / N_IK_HΣ, (NE) / ? other monograms, Sear #1466; BMC Macedonia p. 110, 10 - 16. Head of goat and one ivy-leaf under Strymon's head are slightly visible. Imitations from Serdi region weren't used to fool Macedonian traders but as their own currency. This coin is one of overstrikes on official Macedonian coins which prooves this theory.

type: (A?)5B; imitation of: SNG Copenhagen 1298-9 var.
(2) Serdi
/Files/Images/Coinsite/CoinDB/Strymon_4.jpg
An AE unit struck 168-31 BC in Thrace
Obverse: Head of rivergod Strymon right

Reverse: Wide trident; MAKE / ?ΔONΩN?

Diameter: 22 mm
Die Orientation: 0 H
Weight: 6.7 g

Celtic imitation of Macedonian issue from 185-168 BC. Overstrike of Thessalonica, 158-31 BC, head of Dionysos with ivy wreath right, goat standing right, ΘEΣΣA_ΛO / N_IK_HΣ, (NE) / ? other monograms, Sear #1466; BMC Macedonia p. 110, 10 - 16. Wave on Strymon's face is relic of original coin also there is slightly visible inscription (perpendicular to trident). Imitations from Serdi region weren't used to fool Macedonian traders but as their own currency. This coin is one of overstrikes on official Macedonian coins which prooves this theory.

type E3A, imitation of: SNG Copenhagen 1298-9 var.