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.

Latin: Ergo iam dextro Suebici maris litore Aestiorum gentes adluuntur, quibus ritus habitusque Sueborum, lingua Britannicae propior. Matrem deum venerantur. Insigne superstitionis formas aprorum gestant: id pro armis omniumque tutela securum deae cultorem etiam inter hostis praestat. Rarus ferri, frequens fustium usus. Frumenta ceterosque fructus patientius quam pro solita Germanorum inertia laborant. Sed et mare scrutantur, ac soli omnium sucinum, quod ipsi glesum vocant, inter vada atque in ipso litore legunt.

English: So now we turn back; and on the eastern shore of the Baltic Sea we find the tribes of the East-men dwelling along the coast; in their religion and in their fashions they are Suabians, but their language is more like the British. They worship the mother of the gods and, as a religious symbol, they carry images of wild boars. The symbol serves instead of arms and every kind of assistance, and gives the devotee of the goddess a sense of safety even in the midst of foes. Iron is scarce among them, and the use of the war-club is common. They cultivate grain, and also fruit trees, with more patience than is usually exhibited by the indolent Germans; and, besides this, they even search the sea, for they alone among mankind gather amber, or “glesum” as they call it, in the shallows and along the shore.

Tacitus, The Agricola And Germania.

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