The unwillingness of Nambudiris to adapt to changes in wider society persisted until the early years of the 20th century but Susan Bayly believes that their decline in significance can be traced to the period 1729-1748 when Marthanda Varma established the Kingdom of Travancore and chose to use Deshastha Brahmins from Tamil Nadu in his civil service. She believes that decision undermined the relationship between the Nambudiri Brahmins and royalty in the region, although others have said that Varma's influence was short-lived and that the main cause of change was the arrival of British colonial administrators, such as Colin Macaulay and John Munro, from the early 1800s. After the passing of the Charter Acts of 1833 and 1853 in the British Parliament, the British encouraged the work of Christian missionaries, notably in provision of education, and began the introduction of a judicial system that would have a significant impact on the landholdings, inheritance customs and marriage arrangements of both the Nambudiris and Nairs. The traditional basis of life was challenged by these and other changes, affecting also the other major ethnic groups of the area, such as the Ezhavas and the Syrian Christians.