ors , ▁and ▁the ▁ecc les iast ical ▁principal ities ▁of ▁the ▁Rh ine ▁bul ked ▁largely ▁in ▁German ▁history . ▁ ▁Pr uss ia ▁first ▁set ▁foot ▁on ▁the ▁Rh ine ▁in ▁ 1 6 0 9 ▁by ▁the ▁occupation ▁of ▁the ▁Duch y ▁of ▁Cle ves ▁and ▁about ▁a ▁century ▁later ▁Upper ▁Gu eld ers ▁and ▁Mo ers ▁also ▁became ▁Pr uss ian . ▁At ▁the ▁peace ▁of ▁Bas el ▁in ▁ 1 7 9 5 , ▁the ▁whole ▁of ▁the ▁left ▁bank ▁of ▁the ▁Rh ine ▁was ▁res igned ▁to ▁France , ▁and ▁in ▁ 1 8 0 6 , ▁the ▁R hen ish ▁princes ▁all ▁joined ▁the ▁Confeder ation ▁of ▁the ▁Rh ine . ▁ ▁After ▁the ▁Congress ▁of ▁Vienna , ▁Pr uss ia ▁was ▁awarded ▁the ▁entire ▁Rh in eland , ▁which ▁included ▁the ▁Grand ▁Duch y ▁of ▁Berg , ▁the ▁ecc les i astic ▁elect or ates ▁of ▁T rier ▁and ▁C ologne , ▁the ▁free ▁cities ▁of ▁A achen ▁and ▁C ologne , ▁and ▁nearly ▁a ▁hundred ▁small ▁lord ships ▁and ▁ab be ys . ▁The ▁Pr uss ian ▁Rh ine ▁province ▁was ▁formed ▁in ▁ 1 8 2 2 ▁and ▁Pr uss ia ▁had ▁the ▁tact ▁to ▁leave ▁them ▁in ▁und ist urbed ▁possession ▁of ▁the ▁liberal ▁institutions ▁to ▁which ▁they ▁had ▁become ▁acc ustom ed ▁under ▁the ▁republic an ▁rule ▁of ▁the ▁French . ▁In ▁ 1 9 2 0 , ▁the ▁districts ▁of ▁E up en ▁and ▁Mal med y ▁were ▁transferred ▁to