Frédéric Émile d'Erlanger

On 30 June 1858, Friedrich Emil Erlanger married a young Parisian socialite, Florence Louise Odette Lafitte (1840–1931). Her grandfather, Jacques Laffitte, was a banker, governor of the Bank of France, Finance Minister, and Prime Minister of France temporarily. In 1859, d'Erlanger officially took over the business of the banking house in Paris. He changed his name and was afterwards called Frédéric Émile Baron d'Erlanger. His marriage failed, however. The couple had no children and they divorced in December 1862.

On 3 October 1864, Baron d'Erlanger married the American Marguerite Mathilde Slidell (1842–1927), the daughter of the influential American lawyer, businessman and politician John Slidell (1793–1871). Slidell was the Ambassador of the Confederate States of America at the court of Emperor Napoleon III. His wife, Maria Mathilde Deslonde, was from an influential Creole family whose ancestors emigrated from Brest, France, in the seventeenth century. D'Erlanger met his second wife in New Orleans during a trip to America. She grew up on the prosperous plantation Belle Pointe in Laplace, Louisiana, 25 miles (40 km) west of New Orleans. Later, she moved with her family to Paris, where she and her sister received great attention because of their extraordinary beauty. Her sister Marie Rosine married the Comte de Saint-Roman. D'Erlanger and his wife built a villa situated in the affluent 16th Arrondissement of Paris that still exists today. The access roads to the villa, "Villa Erlanger" and "Rue Erlanger", are named in his honor. In 1870, shortly before the outbreak of the Franco-Prussian War, the family moved to London. The headquarters of the banking house moved there from Paris as well. D'Erlanger resided at 139 Piccadilly in London, the former home of Lord Byron. The German-born baron and all his family members became British citizens. He was authorized to use his foreign titles of nobility, despite some strong opposition at first.

The couple had four children. Raphael Slidell d'Erlanger (1865–1897) was a zoologist and professor at Heidelberg. Baron Emile Beaumont d'Erlanger (1866–1939) later successfully took over the bank's management. Baron Frédéric Alfred d'Erlanger (1868–1943) became a banker, but later acquired acclaim as a composer. François Rodolphe d'Erlanger (1872–1932) was a musicologist and painter whose palace, Ennejma Ezzahra in Sidi Bou Said, Tunisia, now houses the Centre des Musiques Arabes et Méditerranéennes. The latter's son Leo Frédéric Alfred Baron d'Erlanger (1898–1978) eventually became the head of the family-owned bank.

Baron d'Erlanger was one of the leading bankers of Paris, the dominant financial center of continental Europe in the second half of the 19th Century. He invented high-risk bonds, especially for developing countries. Towards the end of the 1850s, Erlanger was able to terminate a banking crisis in Sweden with his bonds; since he became banker of Scandinavian governments. In 1862 Erlanger & Sons issued the first Egyptian government bond, together with the Frankfurt bank Sulzbach brothers, namely Siegmund Sulzbach de (1813–1876) and Rudolf Sulzbach de (1827–1904), with whom he also worked together on railroad bonds. He invested in railroads and mines in Africa, North America, South America, and Europe, as well as Russian and Tunisian government bonds and Southern cotton during the American Civil War. Other than most German and European banks he bet on the southern states during the American Civil War. In the late 1870s Erlanger invested in the British enterprise Alabama Great Southern Railway Company Limited which funded the takeover of Alabama Great Southern Railway and Cincinnati, New Orleans and Texas Pacific Railway (CNO&TP). This railroad net, also known as „Erlanger System“, consisted of over 1,100 miles. He also financed the Swiss Simplon Tunnels between the Valais and Aosta Valley, then the largest railway tunnel in Europe. In 1884 Erlanger accompanied the IPO of the Imperial Royal Austrian State Railways. In 1870 he saved the House of Thurn und Taxis after the crash of Belgian speculator André Langrand-Dumonceau.

The Erlanger Health System in Chattanooga, Tennessee

Along with Paul Julius Reuter (1816–1899), the founder of Reuters news agency, his bank, Erlanger Ltd., funded the construction of a French transatlantic telegraph cable in 1869. His wife, Mathilde, Baroness d'Erlanger, sent the historic first message. In 1889, during an inspection tour of their American railroad investments, the couple created the d'Erlanger Grant for start-up capital to build a hospital in Chattanooga, Tennessee. It is known today as the Erlanger Health System. Erlanger, Kentucky was named to honor the d'Erlangers' financial contributions.

In 1904 however, the Erlangers sold their Frankfurt branch to Dresdner Bank and concentrated on their French and British branches. The main reason may have been the earlier deaths of Ludwig Gottlieb Friedrich von Erlanger (1836–1898), Viktor Alexander von Erlanger (1840–1896) and Carlo von Erlanger (1872–1904). Yet competition by big trading banks may have contributed, just as relocation of banks to Berlin and stricter stock exchange legislation.

As music lovers and influential members of the haute bourgeoisie who had personal relationships with the leaders of many countries, they promoted Richard Wagner and his music, including the first performance of Tannhäuser at the Paris Opera after the Franco-Prussian War. D'Erlanger also donated several art works, including the seventeenth-century allegorical tapestries depicting the Duke of Alba to the Hampton Court Palace of the British crown.

The d'Erlangers also funded the rescue of the murals from the Quinta del Sordo in 1873. This house, which they bought, was temporarily residence of Francisco de Goya. Goya's Pinturas Negras were costly to save from destruction. These "black paintings" that Goya painted directly on plaster, were gently transferred to canvas. After their lack of public acceptance at the Paris Exposition of 1878. These works were given to the Prado in Madrid two years later.

In 1866, Baron d’Erlanger and M. Armand Lalande purchased Châeau Léoville Poyferré in Bordeaux for one million Francs and ran it successfully until the 1890s.

In Italy, the d'Erlangers leased Villa Foscari, the famous mansion built in the seventeenth century by Andrea Palladio, and commissioned restoration work.

Frédéric Emile, Baron d'Erlanger died in Versailles on 22 May 1911. His second son, Baron Emile Beaumont d'Erlanger, had previously succeeded him in the management of the bank.