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'''Michelangelo Ricci''' (1619–1682) was an [[Italy|Italian]] [[mathematician]] and a [[Cardinal of the Roman Catholic Church]].

== Biography ==

Michelangelo Ricci was born on 30 January 1619 in [[Rome]], then capital of the [[Papal States]], to a family of low social standing that originated in Bergamo.  He died in Rome, age 63, on 12 May 1682.

He studied [[theology]] and [[law]] in Rome, where he was a contemporary of [[Rene de Sluze]] - also mathematics under [[Benedetto Castelli]] who himself had been a student of [[Galileo Galilei]]. He was a friend of [[Evangelista Torricelli]], kept close links with contemporary scientific culture, and played an important role in the development of the [[Galileo Galilei|Galilean]] school.

Like de Sluze, he spent his entire career in the [[Roman Catholic Church]] and served the [[pope]] in various roles on several occasions.  A trained theologian, he acted as consultant to various Congregations of the [[Roman Curia]].  Having suffered from [[epilepsy]] since his birth, he was (according to [[canon law]] of the time) disqualified from [[ordination]].  Nonetheless, he was created a [[Cardinal-Deacon]] in the [[papal consistory|Consistory]] of 1 September 1681 by Pope [[Innocent XI]], with the title 'Cardinal-Deacon of [[Santa Maria in Aquiro]]'.  His position in the church was very useful for protecting his friends and fellow scientists in their controversies with the opposing [[scholasticism|scholastic school]].

He played a significant part in the theoretical debates and experiments that led up to Torricelli's discovery of [[atmospheric pressure]] and invention of the mercury [[barometer]].  In particular he followed the experiments in this field by [[Gasparo Berti]], in Rome.

There is an unpublished manuscript by Ricci, devoted to [[algebra]], in the library of the Mathematical Institute of [[Genoa]].  It shows that by 1640 he was familiar with the '[[New Algebra]]' of [[François Viète]].  In this book he provides a critique of the solutions given by the geometer [[Marino Ghetaldi]] of [[Republic of Ragusa|Ragusa]] in his ''De Resolutione et Compositione Matematica'' to the problems posed by [[Apollonius of Perga]].<ref>Ronald Calinger : [http://books.google.fr/books?id=D21wKHoYGg0C&pg=PA122&lpg=PA122&dq=De+resolutione+et+de+compositione+mathematica&source=bl&ots=FThoEjnDa5&sig=5yTkdDC6cUIliOY5CxG8QvIjPPM&hl=fr&ei=vbIlTMqaOYi6jAffyMGUAQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBcQ6AEwAA#v=onepage&q=De%20resolutione%20et%20de%20compositione%20mathematica&f=false Vita mathematica: historical research and integration with teaching]</ref>

His published mathematical work is summarised in a treatise of nineteen pages, ''Exercitatio geometrica, de maximis et minimis'' (1666) in which he studies the maxima of functions of the form <math>x^m(a - x)^n</math> and [[tangent]]s to curves with equation <math>y^m = kx^n</math>, using methods that are an early form of [[Mathematical induction|induction]].  This treatise was much admired by his contemporaries and has recently been republished as an appendix to [[Nicholas Mercator|Mercator]]'s 'Logarithmo-Technia' (1688).  He also studied [[spiral]]s (1644) and [[cycloid]]s (1674) and recognised that the study of tangents and the calculation of areas are reciprocal operations.

Ricci is also known for his correspondence with Torricelli, [[Vincenzo Viviani]], Rene de Sluze and Cardinal [[Leopoldo de' Medici]], founder of the [[Accademia del Cimento]]. These letters give his thoughts on [[paraboloid]]s and [[hyperboloid]]s when cut by parallel planes, on the surface of a ring, and on the properties of the vacuum.  It was Ricci who welcomed [[Marin Mersenne]], when he came to Italy to present the work of [[René Descartes]]. In [[optics]] he studied the magnifying effect of [[lens (optics)|lens]]es. With [[Giovanni Battista Baliani]] he discussed the Galilean revolution.

Following the death of Torricelli and the disappearance of [[Bonaventura Cavalieri]], he was requested to collate and publish his correspondence with these two men.  However he declined the invitation, leading to Torricelli's work being forgotten for some time.

He endeavored to defend [[Francesco Redi]] against Cardinal [[Leopoldo de' Medici|Leopold]] when Redi published his ''Esperienze Intorno alla Generazione degl'Insetti'', arguing against the [[spontaneous generation]] of [[insects]].

Ricci was also the backer of Abbot Francisco Nazzari in the publication of the first review of Italian literature, the ''Giornale de' Letterati'' (1668-1683).

== Works ==

* ''Michaelis Angeli Riccii Geometrica exercitatio'', Romae: apud Nicolaum Angelum Tinassium, 1666
* ''Decretum sacrae Congregationis indulgentijs, sacrisque reliquijs praepositae'', Romae et Pataui: typis reuerendae Camerae Apostolicae, 1678
* ''Decretum Aloysius card. Homodeus'', Romae, et Pataui, Romae et Pataui: typis reuerendae Camerae Apostolicae, 1678
* ''Decretum sacrae Congregationis Indulgentiarum'', Romae: typis reuerendae Camerae Apostolicae, 1679
* ''Logarithmotechnia Nicolaus Mercator. Beigebunden Exercitatio geometrica'', Hildesheim; New York: Olms, 1975

== Potential identity confusion ==

The name 'Ricci' is well known in the field of [[tensor]] algebra, with such concepts as [[Ricci curvature]].  These relate to the work of another Italian mathematician [[Gregorio Ricci-Curbastro]], 1853 - 1925, not to the subject of this article.

== Sources ==
This article is wholly based on the corresponding pages in the French, Italian and Spanish Wikipedias

* «RICCI MICHELANGELO, Cardinale». In: [[Gaetano Moroni]], ''Dizionario di erudizione storico-ecclesiastica'', Vol. LVII, Venezia: Tipografia Emiliana, 1852, p.&nbsp;177
* ''Vitarum Italorum doctrina excellentium qui saeculo XVIII floruerunt decas I-VI. Auctore [[Angelo Fabroni]]o'', Romae: typis S. Michaelis apud Junchium: prostant venales apud Natalem Barbiellini in foro Pasquini, 1769, Vol. II, p.&nbsp;200

== External links ==
* {{en icon}} [http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Ricci.html Biography on the University of Saint-Andrews site]
* {{en icon}} [http://www.imss.fi.it/vuoto/ericci.html Biography on the History of Science Museum, Florence, site]
* {{it icon}} [http://www.francescoredi.it/database/redi/redi.nsf/b4604a8b566ce010c125684d00471e00/d10e6fb0196e68b0c12569fb004f80fa!OpenDocument  Biography on a site devoted to Francesco Redi]
* {{en icon}} [http://www.fiu.edu/~mirandas/bios1681.htm#Ricci The Cardinals of the Holy Roman Church, Biography]

== References ==
{{reflist}}

{{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
| NAME              = Ricci, Michelangelo
| ALTERNATIVE NAMES = Riccius, Michael Angelus
| SHORT DESCRIPTION = Mathematician and Roman Catholic Cardinal
| DATE OF BIRTH     = 30 January 1619
| PLACE OF BIRTH    = Rome
| DATE OF DEATH     = 12 May 1682
| PLACE OF DEATH    = Rome
}}
{{DEFAULTSORT:Ricci, Michelangelo}}
[[Category:1619 births]]
[[Category:1682 deaths]]
[[Category:Italian mathematicians]]