Battle of Gaugamela main Persian infantry was poorly trained and equipped in comparison to Alexander's pezhetairoi and hoplites. The only respectable infantry Darius had were his 2,000 Greek hoplites and his personal bodyguard, the 10,000 Immortals. The Greek mercenaries fought in a phalanx, armed not with a heavy shield but with spears no longer than three metres, while the spears of the Immortals were two metres long. Among the other Persian troops, the most heavily armed were the Armenians, who were armed the Greek way and probably fought as a phalanx. The rest of Darius' contingents were much more lightly armed; the main
Thracian Sea Xanthi and the Rhodope regional units. Islands includes Thasos and Samothrace in Greece and Gökçeada (Imvros in Greek) and Bozcaada (Tenedos in Greek) in Turkey. The bays and gulfs includes the Ierissian Gulf to the southwest, the Strymonian Gulf where the Strymon River empties, the Kavala Gulf and the Saros Gulf in Turkey. Rivers emptying into this portion of the gulf include the Nestos and the Evros/Meriç. The famous thermal springs are Loutra Eleftheron in Kavala. Thracian Sea The Thracian Sea (, "Thrakiko Pelagos"; ) is a sea that is part of the Aegean Sea and forms the northernmost point