Johann Reinhold Forster (; 22 October 1729 – 9 December 1798) was a German Reformed pastor and naturalist. Born in Dirschau, Pomeranian Voivodeship, Polish–Lithuanian Commonwealth (now Tczew, Poland), he attended school in Dirschau and Marienwerder before being admitted at the Joachimsthal Gymnasium in Berlin in 1745. Skilled in classical and biblical languages, he studied theology at the University of Halle. In 1753, he became a parson at a parish just south of Danzig. He married his cousin Justina Elisabeth Nicolai in 1754, and they had seven children; the oldest child was George Forster, also known as Georg.

In 1765, Forster was commissioned by the Russian government to inspect the new colonies on the Volga. Accompanied by George on the journey, he observed the conditions of the colonists and made scientific observations that were later read at the Russian Academy of Sciences. After making a report that was critical of the Russian administration, Forster left for England without payment in 1766. In England, Forster became the successor of Joseph Priestley as tutor in modern languages and natural history at Warrington Academy where he worked for two years. He made contact with many other naturalists, published a textbook on mineralogy and translated works of the apostles of Linnaeus into English. Invited by the geographer Alexander Dalrymple, Forster moved to London in 1770 in preparation for participation in an East India Company expedition, but the plans fell through. Forster continued to publish translations and scientific works including contributions to North American zoology and botany. In February 1772, he was elected a Fellow of the Royal Society.

After the withdrawal of Joseph Banks from the second voyage of James Cook, Forster accepted the position of naturalist on Cook's ship, where he was accompanied by his son George as draughtsman and assistant. On their three-year journey, they made the first recorded crossing of the Antarctic Circle and made observations and discoveries in New Zealand and Polynesia. When they returned to England, Forster published the botanical work . However, there was disagreement with Cook on who should write a narrative of the journey. After a lengthy argument, George wrote A Voyage Round the World, which appeared six weeks before Cook's account. Forster separately published his scientific Observations Made During a Voyage Round the World.

Forster's pride and obstinacy caused him to fall out with many powerful men in England; after clearing some of his substantial debt with the aid of German patrons, he returned to Germany where he was a professor at the University of Halle from 1780. He oversaw the university's botanical garden for a few years and published in a wide range of sciences. Forster died in 1798 and is buried in Halle. He is commemorated in the names of various species of plants and animals, including the genera Forstera and Forsterygion.

Early life and education Johann Reinhold Forster was born on 22 October 1729 in Dirschau, Pomeranian Voivodeship, Polish–Lithuanian Commonwealth (now Tczew, Poland). Forster's family traced its origins to a Yorkshire-born ancestor called George Forster, a descendant of the Scottish Forrester family. This ancestor had emigrated from England after supporting the losing Royalist side in the English Civil War and had become a merchant in Neuenburg (Nowe) in the 1640s. Forster's father was Georg Reinhold Forster and his mother was Eva Plaht, the daughter of Dirschau's mayor Johann Wolff and the widow of Martin Plaht. Georg Reinhold became mayor of Dirschau in 1733 (as the third Forster in this position) but became an invalid in 1735 and had to retire as mayor. Forster attended a Latin school in Dirschau, and then went to Marienwerder (Kwidzyn) to attend the gymnasium in 1743.

In May 1745, Forster was admitted at the Joachimsthalsches Gymnasium in Berlin, a reputable institution. His teachers included , the school rector, who taught theology, Hebrew, Roman antiquity and philosophy; and , the school librarian, who taught history, literature, Latin and natural philosophy. Forster quickly became skilled in classical and biblical languages including Coptic and fluent in Latin. He graduated in 1748 together with , who became a lifelong friend. Other friends and acquaintances included Louis de Beausobre, and Carl Gottfried Woide. Forster also sought out the friendship of foreign students to improve his knowledge of modern languages, especially French.

After his time at the gymnasium, Forster wanted to study medicine at the University of Halle but his father wanted him to study law. As a compromise, Forster studied theology in Halle. Little is known about his student days. His academic teachers included theologian Siegmund Jakob Baumgarten and orientalist .

By July 1751, Forster had arrived in Danzig (Gdańsk), where he was a candidate for ordination at the Reformed church of . He had a meagre income, and his preaching workload did not allow him to pursue his scholarly interests. His sermons were praised, and his superiors contemplated sending him abroad for additional training. Forster was ordained in Königsberg in August 1753 and (possibly to please his father) accepted the post of parson of the Hochzeit-Nassenhuben parish just south of Danzig, starting there on 23 September 1753.

Marriage and work as pastor

Forster had courted his cousin Justina Elisabeth Nicolai since 1751, but was unable to marry her on his income at the time. His father died on 15 November 1753, not long after Forster obtained the post in Nassenhuben, and Forster sold the family house in Dirschau soon after, in 1754. He married Justina Elisabeth on 26 February 1754 at St Peter and Paul in Danzig. Between 1754 and 1765, they had seven children who survived childbirth, including the eldest son, Johann George Adam Forster, also known as Georg Forster.

Forster spent some of his inheritance on his library, collecting thousands of books. He concentrated on scholarly work (especially Egyptian languages such as Coptic) to the detriment of his duties as a pastor. Sometimes he fell asleep during the church service only to be woken to deliver his sermon. Forster expected to move to a position in Danzig after the one in Nassenhuben, following existing precedent, but this did not materialise. In 1757, he wrote to the mathematician Leonhard Euler in an attempt to find a position at the new Imperial Moscow University; while he obtained a recommendation, nothing came of it because of the intensifying Seven Years' War. Russian troops occupied the area surrounding Danzig in May 1758, including the Hochzeit-Nassenhuben parish. Forster did not leave for the relative safety of Danzig, but stayed with his parishioners and protected them against excesses of the occupying Russian troops by directly making demands of the Russian commander-in-chief, William Fermor.

Forster's son George was interested in the study of nature from an early age, and so Reinhold, to satisfy his son's curiosity, bought Carl Linnaeus's and other books, learned natural history from them and then taught his son. Other subjects of this instruction were Latin, French, religion, writing and arithmetic.

Russian expedition

In 1765, Forster obtained leave from his pastoral offices and travelled to St Petersburg with ten-year-old George. Their expenses were paid by Hans Wilhelm Rehbinder, a Russian in Danzig who recommended them to Count Grigory Orlov, the favourite of Catherine the Great. Forster was given a commission to inspect the newly founded colonies near Saratov on the Volga River, with the expectation that his report should show that the Volga German colonists were thriving and happy and to dispel rumours to the contrary. Forster also made scientific plans for the journey, which the Academy of Sciences in St Petersburg supported by providing him with reference books and instruments. The Forsters travelled from Moscow to Saratov in May 1765, continuing via Dmitriyevsk (now Kamyshin) to Tsaritsyn (now Volgograd). They reached the Kalmyk Steppe and Lake Elton (where Forster studied the salt industry) and inspected further settlements along the Volga and some of its tributaries before returning to St Petersburg in October. During the journey, George collected hundreds of plant specimens, helping his father with naming and identification.

Forster made contact with other scientists, and his scientific observations from the journey were read in several sessions of the Academy of Sciences, introduced by the geologist Johann Gottlieb Lehmann. His report for the Russian government was critical of the conditions for the colonists and the officials in Saratov. After it was received by Orlov and Catherine, Forster was asked to draft regulations for the colonies that would include improved governance and some degree of autonomy, and finished this work in May 1766. Forster hoped for a government post, but when that did not come to pass, he asked for permission to leave Russia and payment of 2000 roubles for his time and as compensation for having lost his Nassenhuben post. When he was offered only 1000 roubles, he proudly refused, only receiving 500 roubles from the Russian government much later, in 1771. The Forsters then travelled by ship from Kronstadt to London, where they arrived on 4 October 1766.

Arrival in England and teaching at Warrington Academy When Forster came to London, he knew very little English. He brought a letter of introduction from Friedrich Dilthey, a Reformed pastor in St Petersburg, to Andrew Planta, pastor of the German Reformed congregation in London and assistant librarian at the British Museum. Planta did not receive Forster as warmly as the latter had expected. Instead of an employment opportunity in England, Planta suggested a pastoral vacancy in North Carolina. Based on the recommendation of Forster's school friend Woide, Planta introduced Forster to the naturalist Daniel Solander, who also worked at the British Museum and was a disciple of Linnaeus. Forster sold some items collected during the Russian expedition, including coins and fossils, and tried to find a salaried position to bring the rest of his family to England. He was introduced to the Society of Antiquaries and elected as an Honorary Fellow in January 1767. Based on the observations from the voyage in Russia, he wrote , an essay in Latin on the natural history of the Volga region that was translated into English and then read at the Royal Society and published in the Philosophical Transactions of the Royal Society.

In June 1767, Forster was appointed as tutor in modern languages and natural history at Warrington Academy, replacing Joseph Priestley, with an annual salary of £60. He reunited with his family who came to Warrington in September 1767. Forster taught French, German, and natural history, and published a textbook on mineralogy in 1768. The geologist and science historian Victor Eyles described Forster's approach as "rather more scientific than some of his contemporaries" and giving a "sound grounding in the subject". Forster became a member of the committee of the Warrington Circulating Library and of the masonic lodge "Lodge of Lights No. 148 Warrington". He made the acquaintance of other people interested in natural history, including John Blackburne and his daughter Anna Blackburne of Orford Hall. Forster helped Blackburne with the arrangement of her insect collection and presented his lectures on entomology to her, while she provided him with access to the family library. He also struck up a friendship with the naturalist Thomas Pennant, whom he visited at Downing Hall in the summer of 1768.