There was both public confession in front of witnesses and private confession to a priest. Originally it was public in front of witness (pre nicene), for a long time wearing sackcloth and putting on ashes was widely practised and persisted for a long time.
A book i came across called "Handling Sin:Confession in the Middle Ages" by Peter Biller, He recounts the story recorded by a western monk Ekkehard IV of the St Gall Monastery in Switzerland approx in the years 1030AD. A couple that confessed sexual intercourse on Holy Saturday. He writes:
After having sexual intercourse during easter saturday, the wedded couple lamented their sins in front of their entire household, and subsequently confessed their evil deed in ashes and sackcloth to the parish priest. The priest gave them indulgence, but ordered them to remain standing outside the church for a day and night and banned them from Easter Communion. The couple then turned to the priest of the next village who lived in the odor of sanctity. Still in ashes and cloth they confessed their misdeed to the priest and his flock and asked him if they could recieve communion the next day(which he agreed to)....During mass on Easter Sunday the couple stood outside the church, until the priest showed them in when the Kyrie had been sung. He sealed them at the back of the church. They did not go for communion as they did not find favor with their priest. After communion however , the priest from the next village to say another Mass on behalf of his parishioners and he gave communion to the penitent couple...(The couple) sent a horseman with alms to the neighboring priest, it turned out that he had never left his flock that day..."(pg 48) (basically a synod later proclaimed that it was an angel that appeared before the couple and offered them communion)
The above is an example of both a private and a public confession. The author says the miraculous public confession to the village priest and his flock was not a standard public confession in that public confessions in front of the church was historically only allowed when the bishop presided not a priest,
Regardless, a better question is when did public confession go away altogether in the west? It seems it was still practised and possibly widespread still in the 11th century. As far as the east, private confession to the priest was practised as early as 580 AD as its found in the Nomocanon :
""A spiritual father, if he reveals to anyone a sin of one who had confessed receives a penance: he shall be suspended [from serving] for three years, being able to receive Communion only once a month, and must do 100 prostrations every day. (canon 120)
I notice in your post you wrote "regular" private confession. Confession is indeed emphasized more strongly in the Russian tradition where its expected before Communion. That aspect may have been influence from the Latins.
After the fall of Byzantium to the Ottomons, blessings were given to specialized traveling spiritual confessors to go village to village to preach and hear confessions. Village priests at that time were under-educated so these traveling monks played a vital role. In this case though the 'regular' confession would have become less so after the fall of 1453 not before.
Edited by Kosta, 01 April 2015 - 04:29 AM.