He trained as a surgeon and had an interest in chemistry and biology, publishing several medical articles in The Lancet, one of which argued in favour of the importance of the use of corpses for the study of medicine (it was illegal in England to dissect them at this time).

He spent his time travelling around the eastern States of America preaching, until eventually settling down as a preacher in Philadelphia.

Based upon his newfound understanding of the Bible, Thomas was rebaptised (a third and final time) in 1847 and the groups of congregations and individuals who shared his beliefs continued to grow.

Upon his return to America, Thomas moved from Richmond, Virginia to New York City and began to preach there.

He made a point of speaking to the Jewish community because Dr Thomas had come to believe that Christianity did not replace the Law of Moses but rather fulfilled it.

Instead of having a system of clergy, all the brethren took equal responsibility on a rota to take on the role of presiding and speaking during their meetings.

In order to be exempted from military service, it was required that believers had to belong to a recognised religious group that did not agree with participation in war.

Following his return to America, he made one final tour of the Christadelphian congregations prior to his death on 5 March 1871 in Jersey City.

Thomas did not claim to be any kind of prophet, or in any way inspired, but through study and borrowing from the work of others he believed that many traditional church teachings were incorrect and that from the Bible he could prove that position.

[10] Thomas wrote several books, one of which, Elpis Israel (1848), in its first section, sets out many of the fundamental scriptural principles believed by Christadelphians to this day.