Changes

*545 [[Synod of Brefi]] at Llandewi Brefi in Wales condemns [[Pelagianism]].

*546 [[Columba of Iona|Columba]] founds monastery of Derry in Ireland.

*ca. 550 [[David of Wales]] takes Christianity to Wales.

*553 [[Fifth Ecumenical Council]] held in Constantinople in an attempt to reconcile Chalcedonians with non-Chalcedonians—the ''Three Chapters'' of [[Theodore of Mopsuestia]], [[Theodoret of Cyrrhus]], and [[Ibas of Edessa]] are condemned for their [[Nestorianism]], and [[Origen]] and his writings are also condemned.