other famous physicians and medical researchers of the middle ages include the abbot of monte cassino bertharius, the abbot of reichenau walafrid strabo, the abbess st hildegard of bingen and the bishop of rennes marbodus of angers. monasteries of this era were diligent in the study of medicine, and often too were convents. hildegard of bingen, a doctor of the church, is among the most distinguished of medieval catholic women scientists. other than theological works, hildegard also wrote physica, a text on the natural sciences, as well as causae et curae. hildegard was well known for her healing powers involving practical application of tinctures, herbs, and precious stones. in keeping with the benedictine rule that the care of the sick be placed above all other duties, monasteries were the key medical care providers prior to 1300. most monasteries offered shelter for pilgrims and an infirmary for sick monks, while separate hospitals were founded for the public. the benedictine order was noted for setting up hospitals and infirmaries in their monasteries, growing medical herbs and becoming the chief medical care givers of their districts. the capuchin monks sought a revival of the ideals of francis of assisi, offering care after plague struck at camerino in 1523. healing shrines were established and different saints came to be invoked for every body part in the hope of miraculous cures. some of the shrines remain to the present day, and were in the middle ages great centres for pilgrims, complete with relics and souvenirs. st luke or st michael were invoked for various ailments, and a host of saints for individuals conditions, including st roch as a protector against plague. st roch is venerated as one who provided care to plague suffers, only to fall sick himself and be "healed by an angel". through the devastating bubonic plague, the franciscans were notable for tending the sick. the apparent impotence of medical knowledge against the disease prompted critical examination. medical scientists came to divide among anti-galenists, anti-arabists and positive hippocratics. crusader orders established several new traditions of catholic medical care. the famous knights hospitaller arose as a group of individuals associated with an amalfitan hospital in jerusalem, which was built to provide care for poor, sick or injured pilgrims to the holy land. following the capture of the city by crusaders, the order became a military as well as infirmarian order. the knights of st john of jerusalem were later known as the knights of malta. the knights templar and teutonic knights established hospitals around the mediterranean and through germanic lands. saint albert magnus was a pioneer of biological field research. non-military orders of brothers also took up the service of the infirm. by the 15th century, the brothers of the order of the holy spirit were providing care across europe, and by the sixteenth century the spanish-founded order of st john of god had set up about 200 hospitals in the americas. in catholic spain amidst the early reconquista, archbishop raimund founded an institution for translations, which employed a number of jewish translators to communicate the works of arabian medicine. influenced by the rediscovery of aristotelian thought, churchmen like the dominican albert magnus and the franciscan roger bacon made significant advances in the observation of nature. small hospitals for pilgrims sprung up in the west during the early middle ages, but by the latter part of the period had grown more substantial, with hospitals founded for lepers, pilgrims, the sick, aged and poor. milan, siena, paris and florence had numerous and large hospitals. "within hospitals walls", wrote porter, "the christian ethos was all pervasive". from just 12 beds in 1288, the sta maria nuova in florence "gradually expanded by 1500 to a medical staff of ten doctors, a pharmacist, and several assistants, including female surgeons", and was boasted of as the "first hospital among christians". clergy were active at the school of salerno, the oldest medical school in western europe – among the important churchmen to teach there were alpuhans, later (1058–85) archbishop of salerno, and the influential constantine of carthage, a monk who produced superior translations of hippocrates and investigated arab literature. cathedral schools began in the early middle ages as centers of advanced education, some of them ultimately evolving into medieval universities. the medieval universities of western christendom were well-integrated across all of western europe, encouraged freedom of enquiry and produced a great variety of fine scholars and natural philosophers, including robert grosseteste of the university of oxford, an early expositor of a systematic method of scientific experimentation, and saint albert the great, a pioneer of biological field research. porter wrote that, "the great age of hospital building from around 1200 coincided with the flourishing of universities in italy, spain, france and england, sustained by the new wealth of the high middle ages. ... the universities extended the work of salerno in medical education". renaissance the subject of saint sebastian tended by saint irene, here by jan van bijlert, c. 1620s, became popular in art in the early 17th century, connected with fears of plague and the encouragement of nursing from the 14th century, the european renaissance saw a revival of interest in classical learning in western europe, coupled with and fuelled by the spread of new inventions like the printing press. the fall of constantinople brought refugee scholars from the greek east to the west. the catholic scholar desiderius erasmus (1466-1536) was interested in medicine and influential in reviving greek as a language of learning, and the study of the pre-christian works of galen. roy porter wrote that "after centuries where the church had taught mankind to renounce worldly goods, for the sake of eternity, renaissance man showed an insatiable curiosity for the materiality of the here and now...". in renaissance italy, the popes were often patrons of the study of anatomy and catholic artists such as michelangelo advanced knowledge of the field through such studies as sketching cadavers to improve his portraits of the crucifixion. it is often wrongly asserted that the papacy banned dissection during the period, though in fact the directive of pope sixtus iv of 1482 to the university of tübingen said that the church had no objection to anatomy studies, provided the bodies belonged to an executed criminal, and was given a religious burial once examinations were completed. gregor mendel, augustinian friar and scientist, who developed theories on genetics for the first time. development of modern medicine in modern times, the catholic church is the largest non-government provider of health care in the world. catholic religious have been responsible for founding and running networks of hospitals across the world where medical research continues to be advanced. in 2013, robert calderisi wrote that the catholic church has around 18,000 clinics, 16,000 homes for the elderly and those with special needs, and 5,500 hospitals – with 65 per cent of them located in developing countries. europe the french saint jeanne jugan (1792–1879) founded the little sisters of the poor who specialise in care for the aged. catholic scientists in europe (many of them clergymen) made a number of important discoveries which aided the development of modern science and medicine. catholic women were also among the first female professors of medicine, as with trotula of salerno the 11th century physician and dorotea bucca who held a chair of medicine and philosophy at the university of bologna. the jesuit order, created during the reformation, contributed a number of distinguished medical scientists. in the field of bacteriology it was the jesuit athanasius kircher (1671) who first proposed that living beings enter and exist in the blood (a precursor of germ theory). in the development of ophthalmology, christoph scheiner made important advances in relation to refraction of light and the retinal image. gregor mendel, an austrian scientist and augustinian friar, began experimenting with peas around 1856. mendel had joined the brno augustinian monastery in 1843, but also trained as a scientist at the olmutz philosophical institute and the university of vienna. the brno monastery was a centre of scholarship, with an extensive library and tradition of scientific research. observing the processes of pollination at his monastery in modern czechoslovakia, mendel studied and developed theories pertaining to the field of science now called genetics. mendel published his results in 1866 in the journal of the brno natural history society, and is considered the father of modern genetics. where charles darwin's theories suggested a mechanism for improvement of species over generations, mendel's observations provided explanation for how a new species itself could emerge. though darwin and mendel never collaborated, they were aware of each other's work (darwin read a paper by wilhelm olbers focke which extensively referenced mendel). bill bryson wrote that "without realizing it, darwin and mendel laid the groundwork for all of life sciences in the twentieth century. darwin saw that all living things are connected, that ultimately they trace their ancestry to a single, common source; mendel's work provided the mechanism to explain how that could happen". catholic religious institutes, notably those for women, developed many hospitals throughout europe and its empires. ancient orders like the dominicans and carmelites have long lived in religious communities that work in ministries such as education and care of the sick. the portuguese saint john of god (d. 1550) founded the brothers hospitallers of st. john of god to care for the sick and afflicted. the order built hospitals across europe and its growing empires. in 1898, john was declared patron of the dying and of all hospitals by pope leo xiii. the italian saint camillus de lellis, considered a patron saint of nurses, was a reformed gambler and soldier who became a nurse and then director of romes's hospital of st. james, the hospital for incurables. in 1584 he founded the camillians to tend to the plague-stricken. irishwoman catherine mcauley founded the sisters of mercy in dublin in 1831. her congregation went on to found schools and hospitals across the globe. saint jeanne jugan founded the little sisters of the poor on the rule of saint augustine to assist the impoverished elderly of the streets of france in the mid-nineteenth century. it too spread around the world. in 2017, controversy arose when an associated press report, which the vatican criticized, stated that bambino gesu (baby jesus) pediatric hospital, a cornerstone of italy's health care system and administered by the holy see, put children at risk between 2008 and 2015 and turned its attention to profit after losing money and expanding services. the americas hospicio cabañas was the largest hospital in colonial america, in guadalajara, mexico the spanish and portuguese empires were largely responsible for spreading the catholic faith and its philosophy regarding health care to south and central america, where the church established substantial hospital networks. catholic hospitals were established in the modern united states prior to the american war of independence. the first was probably charity hospital, new orleans, established around 1727. the sisters of saint francis of syracuse, new york, produced saint marianne cope, who opened and operated some of the first general hospitals in the united states, instituting cleanliness standards which influenced the development of america's modern hospital system, and famously taking her nuns to hawaii to work with saint damien of molokai in the care of lepers. st damien himself is considered a martyr of charity and model of catholic humanitarianism for his mission to the lepers of molokai. the catholic church is the largest private provider of health care in the united states of america. during the 1990s, the church provided about one in six hospital beds in america, at around 566 hospitals, many established by nuns. the church has carried a disproportionate number of poor and uninsured patients at its facilities and the american bishops first called for universal health care in america in 1919. the church has been an active campaigner in that cause ever since. in the abortion debate in america, the church has sought to retain the right not to perform abortions in its health care facilities. in 2012, the church operated 12.6% of hospitals in the us, accounting for 15.6% of all admissions, and around 14.5% of hospital expenses (c. 98.6 billion dollars). compared to the public system, the church provided greater financial assistance or free care to poor patients, and was