Question: Prussia is a historical region stretching from Gdańsk Bay to the end of Curonian Spit on the southeastern coast of the Baltic Sea, and extending inland as far as Masuria, Suebi, Goths and other Germanic people lived on both sides of the Vistula River, adjacent to which ancient people first described by the Roman historian Tacitus in his treatise "Germania" (circa 98 CE)?
Context: The Harii (Latinized West Germanic "warriors") were, according to 1st century CE Roman historian Tacitus, a Germanic people.  In his work "Germania", Tacitus describes them as using black shields and painting their bodies ("nigra scuta, tincta corpora"), and attacking at night as a shadowy army, much to the terror of their opponents.  Theories have been proposed connecting the Harii to the einherjar, ghostly warriors in service to the god Odin, attested much later among the North Germanic peoples by way of Norse mythology, and to the tradition of the Wild Hunt, a procession of the dead through the winter night sky sometimes led by Odin. The Vistula Lagoon (Polish: "Zalew Wiślany" ; Russian: Калининградский залив or "Kaliningradskiy Zaliv"; German: "Frisches Haff" ; Lithuanian: "Aistmarės" ) is a brackish water lagoon on the Baltic Sea roughly 56 miles (90 km) long, 6 to 15 miles (10 to 19 km) wide, and up to 17 feet (5 m) deep, separated from Gdańsk Bay by the Vistula Spit.  It is now known as the Vistula Bay or Vistula Gulf.  The modern German name, "Frisches Haff", is derived from an earlier form, "Friesisches Haff". The Vistula Spit (Polish: "Mierzeja Wiślana" ; Russian: Балтийская коса ; German: "Frische Nehrung" ) is an aeolian sand spit, or peninsular stretch of land, which separates Vistula Lagoon from Gdańsk Bay in the Baltic Sea, with its tip separated from the mainland by the Strait of Baltiysk.  The border between Poland (Pomeranian Voivodeship) and Kaliningrad Oblast, an exclave of Russia, bisects it, politically dividing the spit in half between the two countries.  The westernmost point of Russia is located on the Vistula Spit.  The Polish part contains a number of tourist resorts, incorporated administratively as the town of Krynica Morska. Pomerelia (Latin: "Pomerelia" ; German: "Pomerellen, Pommerellen" ), also referred to as Eastern Pomerania (Polish: "Pomorze Wschodnie" ) or Gdańsk Pomerania (Polish: "Pomorze Gdańskie" ), is a historical region in northern Poland.  Pomerelia lay on the southern shore of the Baltic Sea, west of the Vistula river and east of the Łeba river.  Its biggest city is Gdańsk.  Since 1999 the region has formed the core of the Pomeranian Voivodeship.  Pomerelia is part of the historical region of Prussia and is traditionally divided into Kashubia and Kociewie. Curonian Spit National Park (Russian: Куршская коса ) (Also: Kurshskaya Kosa) covers the Russian-owned southern 41 km of the 98 km long, curved Curonian Spit – a type of depositional sandbar.  The spit separates the salt-water Baltic Sea (on the west) from the freshwater Curonian Lagoon to the east.  The southern portion of the spit lies within Zelenogradsky District in Kaliningrad Oblast, Russia; the northern portion lies within southwestern Lithuania.  It is a UNESCO World Heritage Site shared by the two countries. Prussia (Old Prussian: "Prūsa", German: "Preußen" , Lithuanian: "Prūsija" , Polish: "Prusy" ) is a historical region stretching from Gdańsk Bay to the end of Curonian Spit on the southeastern coast of the Baltic Sea, and extending inland as far as Masuria.  The territory and inhabitants were described by Tacitus in Germania in AD 98, where Suebi, Goths and other Germanic people lived on both sides of the Vistula River, adjacent to Aesti (further east).  About 800–900 years later the Aesti were named Old Prussians, who since AD 997 repeatedly successfully defended against take-over attempt by the newly created Duchy of the Polans.  The territory of the Old Prussians and neighboring Couronians and Livonians was unified politically in the 1230s as the Teutonic Order State.  Prussia was politically divided in the period 1466-1772, with western Prussia under protection of the crown of Poland-Lithuania and eastern Prussia a Polish fief until 1660.  The unity of both parts of Prussia remained preserved by retaining its borders, citizenship and authonomy until western and eastern Prussia were also politically re-united under the Kingdom of Prussia.  It is famous for many lakes, as well as forests and hills.  Since the military conquest by the Soviet Army in 1945 and the expulsion of the inhabitants it divided between northern Poland (most of the Warmian-Masurian Voivodeship), Russia's Kaliningrad exclave, and southwestern Lithuania (Klaipėda Region).  The former German state of Prussia (1701–1947) derived its name from the region. In Roman historian Tacitus's first century CE book "Germania", Tacitus describes the veneration of what he deems as an "Isis" of the Suebi.  Due to Tacitus's usage of "interpretatio romana" elsewhere in the text, his admitted uncertainty, and his reasoning for referring to the veneration of an Egyptian goddess by the Suebi—a group of Germanic peoples—scholars have generally held that Tacitus's identification is incorrect, and have debated what goddess Tacitus refers to. The Port of Gdańsk is a seaport located on the southern coast of Gdańsk Bay in the city of Gdańsk (Danzig), extending along the Vistula estuary Martwa Wisła (Dead Vistula), Port Channel and Kashubia Canal.  It is one of the largest seaports on the Baltic Sea. Lithuania is a country in Northern Europe, most populous of the Baltic states, Lithuania has 262 km of coastline consisting of the continental coast and the "Curonian Spit" coast.  Lithuania's major warm-water port of Klaipėda (Memel) lies at the narrow mouth of Curonian Lagoon, a shallow lagoon extending south to Kaliningrad and separated from the Baltic sea by Curonian Spit, where Kuršių Nerija National Park was established for its remarkable sand dunes. The Aesti (also Aestii or Aests) were an ancient people first described by the Roman historian Tacitus in his treatise "Germania" (circa 98 CE).  According to Tacitus, Aestui, the land of the Aesti, was located somewhere east of the "Suiones" (Swedes) and west of the "Sitones" (possibly the Kvens), on the Suebian (Baltic) Sea.  This and other evidence suggests that "Aestui" was in or near the present-day Russian enclave of Kaliningrad Oblast (previously East Prussia).
Answer: Aesti