Ruđer Josip Bošković born in the village Orahov do -Trebinje (18 May 1711 – 13 February 1787) was a theologian, physicist, astronomer, mathematician, philosopher, diplomat, poet, Jesuit, and a polymath from the city of Dubrovnik in the Republic of Ragusa (today in Croatia), who studied and lived in Italy and France.

He is famous for his atomic theory and made many important contributions to astronomy, including the first geometric procedure for determining the equator of a rotating planet from three observations of a surface feature and for computing the orbit of a planet from three observations of its position. In 1753 he also discovered the absence of atmosphere on the Moon.

Bošković was born in village Orahov do Trebiwe in the Republic of Srpska. He was baptized on 26 May 1711 by Marinus Carolis, curatus et sacristia; the name may have been given to him because both his great - grandfather Agostino Bettera and his mother's brother were called Ruggiero, the godparent was his uncle Ruggiero Bettera. He was the seventh child of Nikola Bošković, a merchant born in 1642, at Orahov Do near Ravno in what was then the Ottoman Empire and is now Bosnia and Herzegovina. He knew his father only as a bedridden invalid with paralyzed legs and who died when Ruđer was a child of 10, was rich in trading experience and knowledge of that part of the Ottoman Empire.

Bošković's mother, Paola Bettera (1674 – 1777) was a member of a cultivated Italian merchant family established in Dubrovnik since the early seventeenth century, to where her ancestor, Pietro Bettera, had come from Bergamo in northern Italy. She was a robust and active woman with a happy temperament who lived to 103. She left nothing in writing, but Bošković's aunt, her sister, wrote poetry in Italian. Their sons, Ruđer's cousins and playmates, Antun Bošković and Franjo Bošković, grew up into good Latinists. His own brothers and sisters were all older than himself, except his sister Anica Bošković (1714 – 1804), two years his junior. His eldest sister Mare Bošković, nineteen years his senior, was the only member of the family to marry; his second sister Marija Bošković became a nun in the Ragusa Convent of St Catherine’s. His eldest brother Božo Bošković (Boško), thirteen years older, joined the service of the Ragusa Republic. His brother Bartolomej (Baro) Bošković, born in 1700 and educated at the Jesuit school in Dubrovnik, left home when Roger was 3 to become a scholar and a Jesuit priest in Rome. He too wrote good verse in both Latin and "Illyrian" (early Croatian language), but eventually burnt some of his manuscripts out of a scrupulous modesty. His brother Ivan (Đivo) Bošković became a Dominican in a sixteenth century monastery in Dubrovnik, whose church Ruđer knew as a child with its rich treasures and paintings by Titian and Vasari, still there today. His brother Petar (Pero) Bošković, six years his senior, became a poet like his grandfather. He too was schooled by the Jesuits, then served as an official of the Republic and made his reputation as a translator of Ovid, Corneille’s Cid and of Molière. A volume of his religious verse, Hvale Duhovne, was published in Venice in 1729.

At the age of 8 or 9, after acquiring the rudiments of reading and writing from the priest Nicola Nicchei of the Church of St. Nicholas, Ruđer was sent for schooling to the local Jesuit Collegium Regusinum. During his early studies Ruđer Bošković showed a distinct propensity for further intellectual development. He gained a reputation at school for having an easy memory and a quick, deep mind.

On 16 September 1725, Ruđer Bošković left Dubrovnik for Rome. He was in the care of two Jesuit priests who took him to the Society of Jesus, famous for its education of youth and at that time having some 800 establishments and 200,000 pupils under its care throughout the world. We learn nothing from Bošković himself until the time he entered the novitiate in 1731, but it was the usual practice for novices to spend the first two years not in the Collegium Romanum, but in Sant' Andrea delle Fratte. There, he studied mathematics and physics; and so brilliant was his progress in these sciences that in 1740 he was appointed professor of mathematics in the college.

He was especially appropriate for this post due to his acquaintance with recent advances in science, and his skill in a classical severity of demonstration, acquired by a thorough study of the works of the Greek geometers. Several years before this appointment he had made a name for himself with an elegant solution of the problem of finding the Sun's equator and determining the period of its rotation by observation of the spots on its surface.

Notwithstanding the arduous duties of his professorship, he found time for investigation in all the fields of physical science, and he published a very large number of dissertations, some of them of considerable length. Among the subjects were the transit of Mercury, the Aurora Borealis (corona), the figure of the Earth, the observation of the fixed stars, the inequalities in terrestrial gravitation, the application of mathematics to the theory of the telescope, the limits of certainty in astronomical observations, the solid of greatest attraction, the cycloid, the logistic curve, the theory of comets, the tides, the law of continuity, the double refraction micrometer, and various problems of spherical trigonometry.

In 1742 he was consulted, with other men of science, by Pope Benedict XIV, as to the best means of securing the stability of the dome of St. Peter's, Rome, in which a crack had been discovered. His suggestion of placing five concentric iron bands was adopted.

In 1745 Bošković published De Viribus Vivis in which he tried to find a middle way between Isaac Newton's gravitational theory and Gottfried Leibniz's metaphysical theory of monad - points. He developed a concept of "impenetrability" as a property of hard bodies which explained their behavior in terms of force rather than matter. Stripping atoms of their matter, impenetrability is disassociated from hardness and then put in an arbitrary relationship to elasticity. Impenetrability has a Cartesian sense that more than one point cannot occupy the same location at once. Bošković visited his hometown only once in 1747, never to return.

He agreed to take part in the Portuguese expedition for the survey of Brazil and the measurement of a degree of arc of the meridian, but was persuaded by the Pope to stay in Italy and to undertake a similar task there with Christopher Maire, an English Jesuit who measured an arc of two degrees between Rome and Rimini. The operation began at the end of 1750, and was completed in about two years. An account was published in 1755, under the name De Litteraria expeditione per pontificiam ditionem ad dimetiendos duos meridiani gradus a PP. Maire et Boscovicli. The value of this work was increased by a carefully prepared map of the States of the Church. A French translation appeared in 1770 which incorporated, as an appendix, some material first published in 1760 outlining an objective procedure for determining suitable values for the parameters of the fitted model from a greater number of observations. An unconstrained variant of this fitting procedure is now known as the L1 - norm or Least absolute deviations procedure and serves as a robust alternative to the familiar L2 - norm or Least Squares procedure.

A dispute arose between Francis the Grand Duke of Tuscany and the republic of Lucca with respect to the drainage of a lake. As agent of Lucca, Bošković was sent, in 1757, to Vienna and succeeded in bringing about a satisfactory arrangement in the matter.

In Venice in 1758, he published the first edition of his famous work, Theoria philosophiae naturalis redacta ad unicam legem virium in natura existentium (Theory of Natural philosophy derived to the single Law of forces which exist in Nature), containing his atomic theory and his theory of forces. A second edition was published in 1763 in Venice, a third in 1922 in London, and a fourth in 1966 in the United States. A fifth edition was published in Zagreb in 1974.

Another occasion to exercise his diplomatic ability soon arose. The British government suspected that warships had been outfitted in the port of Dubrovnik for the service of France and that therefore the neutrality of the Republic of Ragusa had been violated. Bošković was selected to undertake an ambassadorship to London (1760), to vindicate the character of his native place and satisfy the government. This mission he discharged successfully — a credit to him and a delight to his countrymen. During his stay in England he was elected a fellow of the Royal Society.

In 1761 astronomers were preparing to observe the transit of Venus across the Sun. Under the influence of the Royal Society Bošković decided to travel to Istanbul. He arrived late and then traveled to Poland via Bulgaria and Moldavia then proceeding to Saint Petersburg where he was elected as a member of Russian Academy of Sciences. Ill health compelled him soon to return to Italy.

In 1764 he was called to serve as the chair of mathematics at the University of Pavia, and he held this post with the directorship of the observatory of Brera in Milan, for six years.

He was invited by the Royal Society of London to undertake an expedition to California to observe the transit of Venus in 1769 again, but this was prevented by the recent decree of the Spanish government expelling Jesuits from its dominions. Bošković had many enemies and he was driven to frequent changes of residence. About 1777 he returned to Milan, where he kept teaching and directing the Brera observatory.

Deprived of his post by the intrigues of his associates, he was about to retire to Dubrovnik when in 1773 the news of the suppression of his order in Italy reached him. Uncertainty led him to accept an invitation from the King of France to come to Paris where he was appointed director of optics for the navy, with a pension of 8,000 livres and a position was created for him.

He naturalized in France and stayed ten years, but his position became irksome, and at length intolerable. He, however, continued to work in the pursuit of science knowledge, and published many remarkable works. Among them was an elegant solution of the problem to determine the orbit of a comet from three observations and works on micrometer and achromatic telescopes.

In 1783 he returned to Italy, and spent two years at Bassano, occupying himself with the publication of his Opera pertinentia ad opticam et astronomiam, etc., published in 1785 in five volumes quarto.

After a visit of some months to the convent of Vallombrosa, he went to Brera in 1786 and resumed his work. At that time his health was failing, his reputation was on the wane, his works did not sell, and he gradually fell prey to illness and disappointment. He died in Milan and was buried in the church of St. Maria Podone.

In addition to the works already mentioned Bošković published course material he had prepared for his pupils in mathematics. He also published accounts of his travels from Constantinople to Poland which was published in several expanded editions and translated into French.

Bošković applied himself to practical engineering projects, including several discussions of architectural repair or stability, including repairs to St Peter's Dome, the stability of the Duomo of Milan, repairs to the library of Cesarea di Vienna and a report on the damage to sectors of Rome in June of 1749 due by a whirlwind.

Bošković also was consulted on civil works concerning ports and rivers: Ivica Martinovic has shown the extent to which Bošković applied himself to such works, and lists 13 major works:

Martinovic's paper includes an extensive annotated bibliography on such works.

His atomic theory, given as a clear, precisely formulated system utilizing principles of Newtonian mechanics inspired Michael Faraday to develop field theory for electromagnetic interaction. Other nineteenth century physicists, such as William Rowan Hamilton, Lord Kelvin, and the elasticity theorist Saint Venant stressed the theoretical advantages of the Boškovićian atom over rigid atoms. Some even claim that Boškovićian atomism was a basis for Albert Einstein's attempts for a unified field theory and that he was the first to envisage, seek, and propose a mathematical theory of all the forces of Nature; the first scientific theory of everything.

The scientist Nikola Tesla, a critic of Einstein, claimed in an unpublished interview that Einstein's theory of Relativity was the creation of Bošković:

For his contributions to astronomy, the lunar crater Boscovich was named after him.

The largest multidisciplinary research center in Croatia was named the "Ruđer Bošković Institute" in his honour.

The modern concept of nationality, based on ethnic concepts as language, culture, religion, custom, etc., was developed only in the 19th century. For this reason the attribution of a definite "nationality" to personalities of the previous centuries, living in ethnically mixed regions, is often indeterminable; Bošković's legacy is consequently celebrated by several states: Croatia, Italy and Serbia.

Croatian sources stress that he referred to his Croatian identity. In writings to his sister Anica (Anna), he told her he had not forgotten the Croatian language. When he was in Vienna in 1757, he spotted Croatian soldiers going to the battlefields of the Seven Years' War and immediately rode out to see them, wishing them 'Godspeed' in Croatian. While living in Paris and attending to a military parade where he saw a Croatian unit from Ragusa, his words were: "there are, my brave Croats". The largest Croatian institute of natural sciences and technology, based in Zagreb bears his name. His picture was on Croatian dinar banknotes valid from 1991 until 1994, when the dinar was replaced by the Croatian kuna.

Italians claim that Boscovich was remembered as an Italian. According to Italians, he was born in city with mixed cultures - Croatian and Italian, and higher society of (also Bošković) Dubrovnik was under Italian influence (Roman - Dalmatinian influence). His mother's family came from Italy, and he was under Italian influence in life and career; He moved to Italy at his 14, where he spent most of his life. In some encyclopedias he is described as an Italian scientist. He used Italian language in private purposes, and Voltaire wrote to Bošković in Italian "as a sign of respect". But, Bošković denied that he was Italian. When d'Alembert in one edition of Voyage astronomique et geographique called him Italian, Bošković said that he was Dalmatian from Dubrovnik, and not Italian.

Serbs claim that his family origins were in Montenegro which would actually make him a Montenegrin, although significant part of Montenegrins declare themselves as Serbs. This theory dates back to 1922 when Serbian philosopher Branislav Petronijević declared Bošković's grandfather a Serb from village Orakovo. The village Orakovo does exist, he probably meant Orahov Do that is purely Croatian. That theory, therefore, does not have clear foundations. The Astronomical Society Ruđer Bošković based in the Serbia's capital Belgrade bears his name.