Within the Roman Catholic church, there are two types of priests: the secular clergy and the religious orders

The secular clergy are known as diocesan priests and are usually (though not always) attached to a parish (church) and are accountable to a local bishop and in many ways are the public face of the Catholic church.

Religious orders, by contrast, have more autonomy from the central church. They are not under the jurisdiction of a bishop and can live completely excluded from secular society, depending on the order they belong. Orders such as the Dominicans, Benedictines, Cistercians, Trappists, Franciscans, etc live within their orders, though often will be connected to educational institutions and can run select parishes. In Bombay the Irish Christian Brothers run Our Lady Of Salvation School (Dadar), the Salesians run Don Bosco School (Matunga) Franciscan Missionary Brothers run Saint Francis D'Assisi High School(Borivali) and so on and so forth ...

The Society of Jesus (also known as Jesuits) is another such religious order.

The Society of Jesus (Societas Jesu) The Jesuits
The Society of Jesus commonly called The Jesuits was founded in 1540 by Saint Ignatius Loyola and since then has grown from the original seven members to over 25.000 members who work out of 1,825 houses in 112 countries spread across six continents.
In the intervening 470 years the Society has served the Church with outstanding men - Doctors of the Church in Europe as well as missionaries in Asia, India, Africa and the Americas.
And has produced 41 Saints, 285 Blesseds and scholars famed for their explorations and discoveries in every conceivable field.

Schoolmasters Of Europe
However the Jesuits are especially known for their educational institutions
During the 16th, 17th and 18th centuries, the Jesuits were called the schoolmasters of Europe not only because of their schools but also for their pre-eminence as scholars scientists and the thousands of textbooks they composed.

Íñigo López de Loyola -  From Sword To Cross The Jesuits were founded by Ignatius Loyola (Íñigo López de Loyola) a Spanish knight from a Basque noble family. Iñigo was an unlikely candidate for a saint - a macho knight who enjoyed fencing and fighting and was very much a ladies man - like I said definitely not saint material
While defending Pamplona from the invading French, Íñigo's leg was shattered by a cannon ball and so was taken to the family castle in Loyola to recover.
There he asked for books of romance and chivalry but unfortunately, the house of Loyola had only two books: the Bible and a book on the lives of saints. 
As he read these books,  Iñigo converted from a man who craved worldly fame and pleasure to a man who desired to distinguish himself in the service of the Eternal King - Jesus.
He began to see the saints as courageous knights serving the most regal of monarchs: Christ the King.
By recovery’s end, Iñigo had resolved not only to follow the examples of the saints, but more so, to outdo them in the service of Christ. He then offered his knightly arms to Our Lady at her shrine in Montserrat.

Compañia de Jesus (Companions of Jesus)
After a pilgrimage to Jerusalem, he decided he could serve God best by studying for the priesthood.
While at the University of Paris, his manner of life, his religious views, and gift for leadership attracted followers. And so he gathered a group of six :
Saint Francisco Xavier
Blessed Peter Faber(France)
Diego Laynez (Spain)
Alfonso Salmeron (Spain)
Nicolás Bobadilla (Spain)
Simão Rodrigues de Azevedo (Portugal)
Friends who vowed themselves to poverty and chastity and placed themselves at the disposal of the Pope
This band of energetic well-educated men who desired nothing more than to help others find God in their lives called themselves the Company of Jesus, and also Amigos en El Señor or "Friends in the Lord", because they felt "they were placed together by Christ".

Ad Majorem Dei Gloriam (For The Greater Glory Of God
In 1537, they traveled to Italy to seek papal approval for their order. Pope Paul III gave them a commendation, and permitted them to be ordained priests. These initial steps led to the founding of what would be called the Society of Jesus
Eventually, they decided that it was for God’s greater glory that they unite themselves into a formally constituted organization by the vow of religious obedience to a superior. They drew up a document outlining the characteristics of the religious order they had in mind. The Compañia de Jesus (Companions of Jesus) would be primarily apostolic, not hidden away in some monastery, but out in the world.
Besides the three vows of poverty, chastity, and obedience, they would also make a separate fourth vow: to go anywhere the Pope would send them.
On Sept. 27, 1540, Pope Paul III approved their petition to form a religious order and also approved their constitution without a single word altered.

And so the Society of Jesus was born.

Scholars, Explorers, Scientists
Men like Robert Bellarmine and Peter Canisius spearheaded the Counter Reformation in Europe, courageous men like Edmund Campion assisted the Catholics in England suffering under the terrible Elizabethan persecutions and missionaries like deNobili Claver, González, deBrito, Brebeuf, and Kino brought the Gospel to the ends of the earth. No other order has more martyrs for the Faith.

By 1750, 30 of the world's 130 astronomical observatories were run by Jesuit astronomers

35 lunar craters have been named to honour Jesuit scientists.

The so-called "Gregorian" Calendar was the work of the Jesuit Christopher Clavius, the "most influential teacher of the Renaissance".

Another Jesuit, Ferdinand Verbiest, determined the elusive Russo-Chinese borderand until recent times no foreign name was as well known in China as the Jesuit Matteo Ricci, "Li-ma-teu", whose story is told by Jonathan Spence in his 1984 best seller.

China has recently erected a monument to the Jesuit scientists of the 17th century - in spite of the fact that since 1948 120 Jesuits languished in Chinese prisons.

No other religious order has spent as many man-years in jail as the Jesuit order.

Five of the eight major rivers of the worldwere first charted by Jesuit explorers.

Two of the statues in Statuary Hall in the Capitol in Washington are Jesuits: Eusebio Kino and Jacques Marquette.

A 1978 Brazilian stamp celebrates the Jesuit founding of São Paulo

Spanish Jesuits went to Paraguay in 1607, built settlements which lasted from 1607 to 1767 for the indigenous people and taught them how to govern and defend themselves against the Spanish slave traders. They also taught agriculture, architecture, metallurgy, farming, music, ranching and printing. The Guaraní natives of Paraguay were printing books on art, literature as well as school texts in these settlements before the American revolution.

This Utopia was suddenly crushed by the influential slave traders who were able to intimidate the Spanish crown into destroying the settlements.

King Charles III expelled the Jesuits in 1767 when Paraguay boasted of 57 settlements serving 113,716 indigenous natives. These Jesuit Settlements were called "a triumph of humanity which seems to expiate the cruelties of the first conquerors" by Voltaire - hardly a friend of the Jesuits.

The history of Latin America would have been quite different if this form of settlement had been allowed to develop according to its own momentum, offering democracy a century before North America.

Jesuits Institutions in Bombay
Campion School, Saint Mary's School, ICSE (Mazagaon), Saint Mary's School, SSC (Mazagaon), Saint Xaviers Boys Academy (Churchgate), Saint Stanislaus School (Bandra)
Saint Xavier's College, Saint Xavier's Technical Institute (Mahim)

The Jesuits : History