The year 1786 remains an important landmark in the history of the Church in Malaya and of the history of Penang. A new Vicar Apostolic, Mgr. Garnault was nominated for the leadership of the Vicariate of Siam and Kedah and was endeavoured to visit the four Christian communities established in the South of the Vicariate. The newly elected bishop was the first parish priest of the Church of the Assumption of Blessed Virgin Mary in Penang. From 1810 onwards, the expansion of the church in the Vicariate of Siam and Kedah was in the direction of the south whereby beyond Penang and the Malayan Peninsula and even Singapore which had been attached to the Mission of Siam in 1821.
In 1841, the Mission of Siam was divided and now the southern part comprised of five districts: Singapore, Malacca, Penang, Mergui and Tavoy (two cities of Burma now called Myanmar) was officially installed as he Vicariate of Malaya.
The year 1888 would be also an important landmark for the history of the Church in Malaya as the Apostolic Vicariate of Malaya was becoming the Diocese of Malacca. Evangelisation in the two states of Selangor and Negeri Sembilan had begun. In 1848, the first earliest church in Southern states of Malaya, the Church of the Visitation of Blessed Virgin Mary, Seremban was built. In 1883, Church of St John the Evangelist, the second earliest church became the Cathedral and “Mother Church” of the Archdiocese of Kuala Lumpur.
The year 1955 marked a new beginning in the history of the Church in Malaya-Singapore. The old diocese of Malacca was restricted into a new ecclesiastical province by dividing it into an Archdiocese with two suffragans. The Diocese of Kuala Lumpur comprised of four states in the center of the Peninsula, i.e. the states of Selangor, Negeri Sembilan, Pahang and Terengganu with Bishop Dominic Vendargon as suffragan who was ordained in August 1955. The other was Diocese of Penang, comprising of six states in the northern peninsula and in 1972, Singapore ceased to be a metropolitan See and the two states of Malacca and Johor were detached from it and made the new diocese of Melaka – Johor, a suffragan of Kuala Lumpur.
In the year 1972, the Diocese of Kuala Lumpur was raised to the status of an Archdiocese with two suffragan dioceses, i.e. Penang and Melaka-Johor. Archbishop Dominic Vendargon became the first Archbishop of Kuala Lumpur who was then succeeded by Archbishop Anthony Soter Fernandez in 1983. Most Rev. Murphy Pakiam, in the year 2003, was appointed as the third Archbishop of Kuala Lumpur. Most Rev. Murphy Pakiam retired in 2013. He was succeeded by Archbishop Julian Leow in 2014.