The Celtic Church has existed in one form or another from within a decade of Christ's death and ressurection, it existed as an established church until the reformation, at which point it retreated into small Highland communities, until the 1800's when it was driven underground. Today, the Celtic Church is once again an established organisation, doing as the original Celtic Missionaries did; bringing the message of Christ to the people.

The Most Reverend David Stalker (retired) has been Primus and Bishop of All Fortrenn of the Celtic Apostolic Church (CAC) since it was established in its modern form in August 1995 until 2011.

Bishop MacLeod lives just south of Edinburgh from where he provides reassuring guidance to the church. In addition, he oversees the whole organisation, The Celtic Church in Scotland, comprising the Celtic Apostolic Church (CAC) and the Celtic Order of Saint Adamnan (COSA) which trains and recruits monks and clergy under the watchful eye of its Abbot, The Right Reverend Julian Roche.

Although the Celtic Apostolic Church is based in Scotland, it is becoming a world-wide organisation, with members in Germany, America, Australia, Northern Ireland and the United Kingdom.

It is interesting to note that the antiquity of British Church, has been unequivocally affirmed by five Papal councils during the Middle Ages: At the Council of Pisa, A.D. 1409, the Council confirmed that the British Church took precedence of all others since it was founded out of Jerusalem shortly after the crucifixion of Christ. The Council of Constance in 1419 AD and the Council of Siena in 1423 made similar proclamations. At the Council of Basle in 1431 it was stated that the Celtic Church took precedence of all others because it was founded by Joseph of Arimathaea immediately after the passion of Christ.

Archaeological evidence supports the existence of the Christian church in Britain during the first century with one of the earliest known church structures identified from approximately 140 A.D. This proves the Celtic Church is much older than the Roman Catholic Church, which was began in 326 A.D. by the Emperor Constantine.

Emperor Constantine, who legalized Christianity in the Roman Empire, had grown up in York. His mother, Helen, was a native Britain and a Christian. She was an influence in his conversion to Christianity. According to an account given in Lives of Saints, Published by John J. Crawley & Co, which is based on the writings of Eusebius, when Constantine was defending his empire from an attack by Maxentius with vastly superior forces, he suddenly remembered the crucified Christ his mother worshipped. It was then he knelt down and for the first time in his life prayed to God and received his now famous vision.

Historians traditionally credit St. Ninian with spreading Christianity throughout Scotland in the latter part of the 4th century. However, Christianity had arrived in Scotland long before Ninian began building his monasteries and churches. With the destruction of the Jewish temple in 70 AD. Christians in Jerusalem migrated to Antioch and Ephesus and it was from those cities missionaries continued to migrate from. Sometime around 75 or 80 AD the first missionaries from John's church in
Ephesus came into the northern Brittanic Isles and began building churches. The Church in Ephesus became an important influence to the established churches in northern Britain and Scotland. They accepted John's teaching that Easter should be celebrated at Passover, which became a trademark distinction of the Celtic Church.

Historians record that the Celtic Church played an important role in the early ecumenical councils. The first great council was held In 300 A.D. at the Council of Elvira in Spain. This was a council of all the existing Gallican Churches. The Celtic Church on the European continent was known as the Gallican Church and covered what is present day Spain, France, Switzerland and northern Italy. In Britain the Church was known simply as the Celtic Church. Again, In 314 A.D. three bishops from the Celtic Church in Britain attended the Council of Arles. And at the Council of Nicea in 325 A.D. the Celtic Church was again well represented, whereas the Roman church did not have a single bishop in attendance. In 359 A.D. when over 400 bishops met at the Council of Rimini to deal with the issue of Arianism bishops from the Celtic Church were present. In 600 A.D. when Augustine came to Britain to establish a mission from Rome he was greeted by Christians from St. Martin's Celtic Church (named for St. Martin of Tours), in Canterbury. It was said that he worshipped there until his church could be built.

The Celtic Church was known to the Reformers and much of the liturgy in the Anglican Church was modeled after the Celtic Liturgy. The Orthodox Church recognizes the validity of Anglican Orders in part because several post reformation Anglican bishops were assisted in their ordination by Celtic bishops (CHRISTOPHER HAMPTON, Archbishop of Armagh assisted the Archbishop of Canterbury in at least three Episcopal ordinations in the 17th century). Up to the 12th century it was very common for Roman Catholic bishops to be assisted in their ordination by Celtic bishops.

After the attacks on the monasteries during the reformation the church retreated entirely into the Highlands where worship continued in small communities in oratories and in people's homes. In the early 1800's the church came under attack again when the Highland Clearances began. This forced the church to go underground where it remained until the 20th century.

The Celtic Church was not destroyed or driven away, contrary to much that has been written to that effect. It has survived the ages and is alive and well today.