Bethabara trans Iordanem, ubi Ioannis in paenitentiam baptizabat, unde et usque hodie plurimi de fratribus, hoc est de numero credentium, ibi renasci cupientes vitali gurgite baptizantur.
In loco, ubi Domnus baptizatus est, ibi est una columna marmorea, et in ipsa columna facta est crux ferrea; ibi est et ecclesia sancti Iohannis Baptistae, quam fabricavit Anastasius imperator, quae ecclesia super cameras maiores excelsa fabricata est pro Iordane, quando implet; in qua ecclesia monachi morantur, qui monachi senos solidos per annum de fisco accipiunt pro vita sua transigenda.
(Theodosius, De situ Terrae Sanctae, 20)
Eusebius, Onomasticon 58:18-20 (ca. 295 A.D.); Jerome 59:19-21 (ca. 390 A.D.)
Bethabara (John 1:28) "beyond the Jordan, where John was baptizing" for repentance, and the place is known and to this day many of the brothers, that is, of the believers, who desire to be reborn receive the baptism in that life-giving stream.
Theodosius, De situ Terrae Sanctae, 20
At the place where the Lord was baptized is a marble column, and on top of it has been set an iron cross. There also is the Church of Saint John Baptist, which was erected by Emperor Anastasius. It stands on great vaults which are high enough for the times when the Jordan is in flood. The monks who reside at this church each receive six gold coins a year from the Treasury for their livelihood.
Matth 3:13-17 Jesus is baptized by John the Baptist at the Jordan
Then Jesus came from Galilee to John at the Jordan, to be baptized by him. John would have prevented him, saying, "I need to be baptized by you, and do you come to me?" But Jesus answered him, "Let it be so now; for it is proper for us in this way to fulfill all righteousness." Then he consented. And when Jesus had been baptized, just as he came up from the water, suddenly the heavens were opened to him and he saw the Spirit of God descending like a dove and alighting on him. And a voice from heaven said, "This is my Son, the Beloved, with whom I am well pleased."
Joh 1:28-34 The witness of John the Baptist
This took place in Bethany across the Jordan where John was baptizing.
The next day he saw Jesus coming toward him and declared, "Here is the Lamb of God who takes away the sin of the world! This is he of whom I said, 'After me comes a man who ranks ahead of me because he was before me.' I myself did not know him; but I came baptizing with water for this reason, that he might be revealed to Israel." And John testified, "I saw the Spirit descending from heaven like a dove, and it remained on him. I myself did not know him, but the one who sent me to baptize with water said to me, 'He on whom you see the Spirit descend and remain is the one who baptizes with the Holy Spirit.' And I myself have seen and have testified that this is the Son of God."
MORE ANCIENT SOURCES
Itinerarium Burdigalense 598, 1-2 (333 A.D.)
"Five miles from there in the Jordan is the valley where the Lord was baptized by John, and above the far bank at the same place is the hillock from which Elijah was taken up to heaven."
Anonymus Placentinus, Itinerarium 11 (ca. 570 A.D.)
I kept Epiphany at the Jordan, and on the night special miracles take place at the spot where the Lord was baptized. There is an obelisc there surrounded by a screen, and in the water, where the river turned back in its bed, stands a wooden cross. On both banks there are marble steps leading down to the water. The eve of Epiphany is solemn vigil with an enormous congregation. They begin mattins at the fourth or fifth cock-crow, and at dawn, when mattins is over, the ministers come outside, and, accompagnied by deacons, the priest goes down into the river. The moment he starts blessing the water the Jordan turns back on itself with a roar and the water stays still till the baptism is finished. All the shipowners of Alexandria have men there that day with great jars of spices and balsam, and as soon as the river has been blessed, before the baptism starts, they pour them out into the water, and draw out ships when they are about to set sail. After the baptism every one goes down into the river to gain a blessing. Some wear linen, and some other materials which will serve as their shrouds for burial. And after the baptism the water returns to its place. From the point where the Jordan comes out of the Sea of Tiberiades to where it ends at the Salt Sea is about 130 miles.