Church-goers from across south Wales made a special trip to a Palm Sunday service in Blaenavon to watch the Archbishop of Canterbury in action.
Dr Williams proved a crowd-puller for the service
Dr Rowan Williams led nearly 400 people on a Palm Sunday procession through the town's streets.
He and other clergy walked from St Paul's church to St Peter's.
The parish had asked if he could visit to help celebrate the 200th anniversary of the consecration of St Peter's Church.
Father Jason Bray, the vicar of Blaenavon, said although Dr Williams - the former Bishop of Monmouth and Archbishop of Wales - was quite well-known in the town, he believed it was the first time a serving Archbishop of Canterbury had visited the town.
Dr Williams is the spiritual leader of 70m Anglicans worldwide.
Father Bray invited him to the service following a discussion in a parish meeting.
Two other churches in the town shut down for the morning so their members could take part in the procession and ceremony.
"We had 300 more people than we would normally have for this service," Father Bray told BBC Wales news' website.
"People from all over came, from as far as Monmouth, Swansea and Gower.
"There were a lot of people from the local community, too."
As well as carrying palms through the town, Dr Williams gave the sermon and celebrated the Eucharist in the service.
The Archbishop stayed at the vicarage with the Father Bray's family during the visit.
"He was our bishop here until he went to Canterbury and he inducted me as vicar of Blaenavon three years so, so I know him quite well," Father Bray explained.
"He played with the kids this morning before the service. At one point he was colouring with my son."
Palm Sunday marks the start of Holy Week in the Christian calendar - the week leading up to Easter.
Large palm leaves are often carried on processions to churches and members of the congregation hold small crosses made of palm leaves.