Baron Lionel Nathan de Rothschild was a British banker and politician. He became the first practising Jew to sit as a Member of Parliament in the United Kingdom.
The son of Nathan Mayer Rothschild and Hanna Barent Cohen, he was a member of the prominent Rothschild family. He was born in London, where his father had founded the British branch of the Europe-wide family. Like his father, he was a Baron of the Habsburg Empire, but unlike his father he used the title in British society. Prime Minister Gladstone proposed to Queen Victoria that he be made a peer. She demurred, saying that titling a Jew would raise antagonism and furthermore it would be unseemly to reward a man whose vast wealth was based on what she called "a species of gambling" rather than legitimate trade. However in 1885 the Queen did raise Rothschild's son Nathan to the peerage; he became the first Jewish member of the House of Lords.
Rothschild was responsible for raising large sums for the government, especially in the Crimean war, and for philanthropic relief of Irish famine victims. In 1861 in protest at the suppression of the Polish uprisings, he (initially) refused to contract a loan to Russia. His most famous undertaking was financing the government's purchase of the Suez Canal shares from Egypt for £4 million.
In 1847 Lionel de Rothschild was first elected to the British House of Commons as one of four MPs for the City of London constituency. Because Jews were at that point still barred from sitting in the chamber due to the Christian oath required to be sworn in, Prime Minister Lord John Russell introduced a Jewish Disabilities Bill to remove the problem with the oath. In 1848, the bill was approved by the House of Commons but was twice rejected by the House of Lords. After being rejected again by the Upper House in 1849, Rothschild resigned his seat and stood again winning in a by-election to strengthen his claim.
In 1850, he entered the House of Commons to take his seat but refused to swear on a Christian Bible asking to use only the Old Testament. This was permitted but when omitting the words "upon the true faith of a Christian" from the oath he was required to leave.
In 1851 a new Jewish Disabilities Bill was defeated in the House of Lords. In the 1852 general election Rothschild was again elected but the next year the bill was again defeated in the upper house.
Finally, in 1858, the House of Lords agreed to a proposal to allow each house to decide its own oath. On 26 July 1858 de Rothschild took the oath with covered head, substituting "so help me, Jehovah" for the ordinary form of oath, and thereupon took his seat as the first Jewish member of Parliament. He was re-elected in general elections in 1859 and 1865, but defeated in 1868; he was returned unopposed in a by-election in 1869 but defeated a second time in the general election in 1874.
A patron of thoroughbred horse racing, his colt "Sir Bevys" won the 1879 Epsom Derby.
In 1836, Lionel de Rothschild married his first cousin Baroness Charlotte von Rothschild (1819–1884), the daughter of Baron Carl Mayer Rothschild of the Rothschild banking family of Naples. They had the following children: Lenora (1837 - 1911), Evelina (1839 - 1866), Nathan Mayer (1840 - 1915), Alfred Charles (1842 - 1918), and Leopold (1845 - 1917).
Lionel de Rothschild died in London in 1879, aged 70, after an attack of gout, and his body was interred in the Willesden Jewish Cemetery in the North London suburb of Willesden.