Emanuel de Rohan was born on April 18th 1725 in Mancha Spain in a noble family. Although French, his father Jean had taken refuge in Spain after having been banished from France for having taken part in a conspiracy of which the planned outcome was the instalment of Philip V of Spain on the throne of France. At a young age Emanuel de Rohan served in the court of Madrid and in that of Parma. He also served for a time as ambassador extraordinary to Francis I. After joining the order he served in a number of posts including that of general of the galleys, (1756-1758) and a bailiff of justice, and general of the order's land and sea forces. Towards the end of Grandmaster Pinto's reign de Rohan was already being viewed as a potential successor to the ageing grandmaster. Eventually the successor was to be Francisco Ximenes but he only ruled for two years. He died on November 9th 1775. On November 12th 1775 Emmanuel de Rohan Polduc, then aged fifty, was selected as his successor.

Grandmaster Pinto had spent recklessly, bankrupting the treasury and giving the country an artificial sense of prestige, which however did not sink below the upper levels of society. His successor, Francisco Ximenes (1773-1775) tried to correct the highly precarious financial situation by imposing drastic measures. But in reality, Grandmaster Ximenes completely failed to understand the growing problems which were strangling the country. His ruthless way of administration, especially after the revolt of the priests meant that few lamented his death which occurred on October 18th 1775. Meanwhile the country's problems had remained largely unsolved, a situation which was seriously affecting the lower end of society, which comprised the majority of the population.

It was against this background that De Rohan became grandmaster, in 1775. De Rohan realised that for the country to regain an adequate economic footing the confidence of the common people had to be assured. One of his first orders in fact was the removal of the heads of those who had been executed after the uprising of the priests. These had been left exposed for all to see, so as to serve as a warning to others who could have possibly been harbouring thoughts of revolt. He also stopped the court proceedings of the other accused. He encouraged trade through a number of measures chief of which was the changing over of the order's fleet from one based on war and pirating to one primarily concerned with commerce.

In 1779 the university was reopened, after having been shut down under Ximenes. As regards the order itself de Rohan called a General Chapter, the first time since 1631. Through these and other acts of mercy and charity, de Rohan tried to project himself as a loveable and approachable grandmaster and this quickly won him the respect of many. He mixed freely with the populace. In 1776 as part of this policy he visited the village of Zebbug for the feast of St Philip. The villagers took the opportunity to ask de Rohan to grant their village the status of a city, a request which was granted. In June 1777, Zebbug became Citta' Rohan, in honour of the grandmaster.

De Rohan made legal history in 1784, when he published a code of laws, the provisions of which are mostly still in use to this day. De Rohan's magistracy is also remembered for the formation of the Anglo Bavarian langue in 1783, to which was also incorporated the priory of Poland. A palace close to Fort St Elmo built in 1696 became the auberge of this new langue. De Rohan also made history in that he became the first grandmaster to admit women in his court.

Grandmaster de Rohan is best remembered for the additions he made to the harbour fortifications. The peninsula on which a part of Sliema exists nowadays had long been considered as a possible threat to the defence of Valletta. This had been amply demonstrated during the Great Siege of 1565, when the Turks had set up a battery on the promontory, which after that came to be known as Dragut's point, and from there directed their fire on Fort St Elmo. Should another attack on Malta materialise the enemy would no doubt have made use of such a strategic position once again. For years the issue remained unsolved. Then in 1792 the order, now under de Rohan began to build Fort Tigne, designed by the engineer Tousaud and named as such after the bailiff Tigne who contributed generously towards its construction. The fort is the smallest built by the order in Malta but in spite of its size, its unique shape led to it being considered as one of the strongest set of defences around the harbour. Its design, that of four flanks at right angles to each other with a circular tower at one point acting as a keep, enabled it to house a large number of cannon. Apart from defending Valletta it was also meant to control the entrance into Marsamxett harbour.

Another building associated with De Rohan, is the Biblioteca in Valletta. Built on the design of Stefano Ittar, this was the last important construction undertaken by the order in Malta and work on it started in 1786. It was to serve as a home for the archives and a library and it was accessible to the general public. Grandmaster Emanuel de Rohan was awarded the Stock and Pilier by the Pope.

The last eight years of his magistracy were indeed worrying for de Rohan. In 1789, the revolution in France had sent shockwaves throughout Europe. In the following years the ensuing war in Europe disrupted the political fabric and the order lost many friends from places of power in a number of formerly sympathetic European countries. Their replacements, in line with the new thinking brought about by the revolution, were not as sympathetic to the order, which was viewed as the embodiment of the ancienne regime, the pre revolutionary fabric of society. Moreover a number of revolutionary societies such as the Jacobean club were attracting members from within the order itself regardless of rank. But perhaps the worst affect of the upheavals in Europe for the order was the loss of a great deal of revenue which used to be reaped from most European countries, especially France, which was the first country to confiscates' the order's property there and thus deprive it of a fat portion of income. In spite of this and the threat which the new order posed to the brotherhood, the knights remained neutral over the conflict which was ravaging the continent. But Maltese soldiers were allowed to serve on British ships, which was perhaps France's worst enemy.

During the 1790's the order's financial situation became increasingly worrying. Much was made to stem the flow and the desperate measures included the melting down of some of the silver used in the Sacra Infermeria, the order's hospital and part of the personal dinner service of the grandmaster, after credit amounts had reached their limits. Other efforts were made at wooing help from tsarist Russia first under Catherine the Great and then under her son Paul I who was a great admirer of the order and helped it generously. In return, what had formerly been the grand priory of Poland was converted in 1797 into the priory of Russia. Tsar Paul also assumed the title 'protector of the order'.

De Rohan's health which had never been too good after a stroke he had suffered in 1792, continued to deteriorate as the decade wore on. He died after a short illness on July 13th 1797, the trouble to which he was being subjected no doubt having hastened his demise. As he lay dying he uttered the words 'I, at any rate, am the last grandmaster, at least of an order illustrious and independent,' as if foreseeing what was to become of the brotherhood within the following months. He was mourned by all regardless of any distinction because all had come to love the grandmaster. He was buried in St Johns' cathedral. Within a year of his death, the French invaded Malta and the Order of St. John lost the islands forever.