Frederick Martin (1704-1750) established the ministry on St. Thomas, St. Croix and St. John. One secret of the success of this native of Upper Silesia was the personal interview. In his spare time he went from town to town and attempted to make the personal acquaintance of every black on St. Thomas. Moved by his interest in them, the slaves attended services in the church built on plantation property he had purchased with Moravian funds. In his first year, 700 blacks are reported to have converted to faith in Christ. But when Martin began baptizing them, the local Dutch pastor accused him of not being properly ordained. A trial ensued. Because Martin and his coworkers Matthias Freundlich and his wife would not take an oath, they were fined. Unwilling to pay the fine, they were imprisoned. They remained there three months until Count Zinzendorf arrived. Not knowing of the preceding events, he had them immediately set free. The opposition could not defeat Martin, no matter what they tried. In the castle jail, he preached nightly through the bars to a gathered crowd while his black assistant Mingo preached in the church. Martin died in 1750 in St. Croix. By 1760 the Moravian church in the West Indies reported 1,600 baptized believers and 3,600 souls under the care of the mission.