Sonnenburg in Neumark, Prussia. George Schwartz, his father, was a brewer and baker. His mother's maiden name was Margaret Grundt. Her first husband was Hans Schönemann, by whom she had three children, who all died young. By her second husband, George Schwartz, she had, besides Christian, a daughter, Maria Sophia, three years his senior. On her deathbed (before 1731) she charged her husband and her pastor to devote Christian to the ministry of Christ. At the age of eight he was sent to the grammar school at Sonnenburg, remaining there until his confirmation and first communion. About 1740 he was removed to Küistrin. His father's allowance to him there was beggarly. The syndic, Kern, engaged him to teach his daughter for a small pittance. From Kern Schwartz heard of the Danish missions in India, then largely directed by H. A. Francke, a philanthropical professor of Halle. In 1746 Schwartz entered the university of Halle, boarding at an orphan-house founded by Francke. A copious notebook which he filled during his attendance at the lectures of Baumgarten, Michaelis, and Freylinghausen, at Halle, is preserved by the Society for Promoting Christian Knowledge in London. While becoming proficient in Hebrew, Greek, and divinity, he met Schultz, who had just returned from the Danish mission at Tranquebar, and invited Schwartz's help in his new edition of the Tamil Bible. Schultz inspired Schwartz with a wish to become a missionary, and Francke proposed that he should go out to Tranquebar. With two other missionaries destined for Tranquebar, Huttemann and Poltzenhagen, Schwartz was ordained at Copenhagen by Harboe, bishop of the Danish church, on 17 Sept. 1749. They spent six weeks in London from 8 Dec., and preached several times. Schwartz preached on Christmas day at the Chapel Royal, and afterwards at the Savoy. They also made the acquaintance of Whitefield. On 29 Jan. 1750 they sailed in an East India vessel, the Lynn, from Deal, and, after stormy weather, landed on 17 June at Cuddalore. Thence they travelled to Tranquebar.
The Danish settlement of Tranquebar, formed for trade purposes, was the home of the first mission founded by a reformed church. Frederick IV of Denmark sent thither in 1705 its first missionaries, Ziegenbalgh and Plutscho. With Schwartz and his two companions the missionaries now numbered six or eight. There were 1,674 native converts. The war which Clive was waging with Dupleix for predominance in Southern India left Danish territory almost untouched. With the work in the schools and churches Schwartz's life was bound up for the next twelve years. His first business was to learn Tamil, and his first charge a Tamil school. His power of acquiring languages was remarkable, and he came to speak fluently Tamil, Hindustani, Persian, Mahratta, as well as German, English, and Portuguese. Owing to his zeal and ability the district south of the Caveri, on which the cities of Tanjore and Trichinopoly stand, was entrusted to him. In 1760 he travelled among the Dutch missions in Ceylon.
In 1762, with a brother missionary, he visited Trichinopoly, which was then held by a large English garrison under Major Preston. The latter and the other officers welcomed Schwartz warmly, and offered to build a mud house for a school and church. One incident after another prolonged his stay. In 1764, at Preston's request, he accompanied his troops to the siege of Madura as chaplain, and received for his care of the sick and wounded nine hundred pagodas (360l.) from the nawab of Arcot, who had a palace at Trichinopoly. This sum he devoted to the school for the orphans of English soldiers and the needs of the mission. He actively aided Colonel Wood, the successor of Preston, who fell at Madura, to build a stone church in the fort; and a substantial structure, capable of holding fifteen hundred people, was dedicated as Christ's Church on 18 May 1766. In after years a mission-house and English and Tamil schools were added. In 1768 he received a salary of 100l. a year as chaplain to the troops at Trichinopoly, half of which he devoted to the mission. After much correspondence to and from the authorities in London, Madras, Halle, and Copenhagen, Schwartz in 1770 agreed to settle permanently in Trichinopoly as a missionary and chaplain to the troops under the British flag. His relations with Tranquebar were thenceforth unofficial, although he maintained close relations as a friend and counsellor with the mission there.
Schwartz proved an ideal military chaplain. Until he could speak well enough to preach extempore he used to read sermons of English divines. His piety and self-denial told on officers and men alike. At the same time he pursued his work as a missionary. Five catechists, with whom he prayed morning and evening, went out daily in the city and villages. He made missionary tours to distant places. At Tanjore there had been a Christian community as early as 1759, but in 1773 the nawab of Arcot stormed the city, dethroned the rajah, and destroyed the little mission church. The mission, however, recovered the blow