Tharbad.
Tharbad was the town and port, build about 250 Miles up the river Greyflood, with great quays capable to receive seagoing vessels, build by the Numenorians in the Second Age between 813 - 882 This can be determent by the fact that Aldarion met Galadriel in Tharbad.after his appointment as King of Numenor, on one of his later ( After S.A.883 ) journeys to Middle-Earth, but there is no further describtion of exactly when or why. It may also be asumed the Bridge of Tharbad connecting the later Greenway and the Old South Road was build during the same time and Tharbad may have been fortified from the beginning because of the hostile natives living in Enedwaith and Minhiriath. During the reign of the Numenorians until the war between Elves and Sauron broke out in S.A.1693 Tharbad lived a relatively quit but prosperous life . but when the war in finaly came Tharbad was conquered and Sauron had in the War with Elves and Sauron forces standing at Tharbad and after his defeat at Sarn Ford he retreated and was strengthened by these forces.
The Numenorian Admiral; Ciryatur, who arrived at the very neck of time had send some of his fleet to Lond Daer and up the river and before Sauron could manage to strengthen his worn out army from the East he suddenly found himself with the Numenorians on his heels and he was utterly derouted and escaped back to Mordor.
I assume that at this time Tharbad was largely laid in ruins because of the war but was rebuild to some degree but it never had the same influence again, Eregion and Ost-in-Edhil was destroyed and Numenor had trouble of its own. There is no further references to Tharbad until the realms of Arnor and Gondor are in existence, in the glory time of Arnor and Gondor a new fort was raised there on great earthworks on both sides of the river to guard the once famed Bridge of Tharbad. The quays were ruinous but with long labour a port capable of receiving seagoing vessels were made.
Then it is told that the realms held a considerable garrison of soldiers, mariners and engineers there until
the1700 century of the Third Age. At this time Cardolan and Rhudaur
had ceased to exist and the people of Gondor and Arnor dwindled due to the Dark Plague. The final ruin and desertion
of Thardad came in the T.A.2912 when great floods devastated Enedwaith and Minhiriath.