It has been more than 150 years since William Welch Deloitte opened his own accountancy office across the street from Bankruptcy Court on Basinghall Street in London. Learn all about the history of Deloitte from the timeline below:

1833   At the age of 15, William Welch Deloitte becomes an assistant to the Official Assignee at the Bankruptcy Court in the City of London. This was the ideal apprenticeship at that time for a young man with an interest in the rapidly developing field of public accounting.

1845   Deloitte opens his own accountancy office opposite the Bankruptcy Court on Basinghall Street, London.

1849   In connection with the accounts of the Great Western Railway, W.W. Deloitte becomes the first person ever appointed as an independent auditor. Deloitte makes his reputation in particular through his work in the railroad industry — the "Web" of its day. During the 1850s and 1860s, he develops the system for keeping railway accounts, subsequently adopted as the industry standard, that protected investors from mismanagement of funds. He also develops a system of account-keeping for hotels that was universally adopted by large hotels in Great Britain and overseas.

1854   Royal Charter is granted to the Society of Accountants in Edinburgh, the first organized body of public accountants in the world. Among its founders was Alexander Thomas Niven, under whose tutelage George A. Touche would qualify as an accountant in Edinburgh 29 years later, before setting off for London to practice his profession.

1857   Deloitte accepts his first partner, Thomas Greenwood, who contributed £800 in capital. The firm becomes known as Deloitte & Greenwood.

1867   The Railway Companies Act lays down the auditor's duties and responsibilities. A statutory form of railway accounts was prescribed in 1868, and it is believed that Deloitte played a major part in designing the form and contents of such accounts — probably the first prescribed form of accounts in the modern sense.

1869   Admission to the partnership (at age 24) of John George Griffith, who exercised a major influence on the growth of the firm until his retirement in 1902. For this entire period, the firm is known as Deloitte, Dever, Griffiths & Co.

1880   Royal Charter issued incorporating the Institute of Chartered Accountants in England and Wales, with W.W. Deloitte, Henry Dever, and John Griffiths among the founding members. Philip S. Ross co-founds North America's first accounting society.

1880   First overseas Deloitte office opens in New York. Branches of this New York outpost are subsequently established in Cincinnati (1905), Chicago and Montreal (1912), Boston (1930), and Los Angeles (1945).

1893   Charles Waldo Haskins and Elijah Watt Sells meet in Washington, D.C. while working for the Dockery Commission of the U.S. Congress, which was undertaking the first comprehensive revision of the federal government's accounting practices since the time of George Washington. Two years later, they form a partnership — Haskins & Sells — based in New York City.

1897   Retirement of William Welch Deloitte.

1898   George Touche establishes his own firm in London.

1900   George Touche and John Ballantine Niven form Touche, Niven & Co. in New York. At that time, there were fewer than 500 certified public accountants in the U.S. Staff complement of Deloitte reaches 80 persons. Fees that year total £41,193.

1901   Haskins & Sells opens first regional office in Chicago and first overseas office in London.

1902   For the first time, a "lady typist" (sic) is engaged by the London office of Deloitte.

1905   Deloitte, Dever, Griffiths & Co. becomes Deloitte, Plender, Griffiths & Company. In the Hughes insurance investigation, which rocked the financial world and led to comprehensive revisions in the accounting methods of life insurance companies, Deloitte's New York office collaborates for the first time with the firm of Haskins & Sells.

1911   Firm of George A. Touche & Co. is established in Canada.

1917   George Touche is knighted by George V. Three years later, he is made a baronet of the United Kingdom.

1925   Two of our U.K. and U.S. predecessor practices form a co-partnership in several countries under the name Deloitte, Plender, Haskins & Sells.

1933   Congressional testimony by Haskins & Sells Managing Partner Arthur Hazleton Carter is instrumental in promoting the establishment of the SEC, as well as the requirement that public accountants audit the financial statements of all publicly traded companies.

1947   George Bailey & Co. is formed. Merges with Allen R. Smart & Co. and Touche, Niven & Co. to become Touche, Niven, Bailey & Smart. The first partners' meeting, held in Highland Park, Illinois, is attended by the firm's 33 partners. Net service revenues for the first year are US$3.6 million.

1952   Nobuzo Tohmatsu qualifies as a certified public accountant in Japan and becomes a partner in a foreign-affiliated accounting firm.

1952   Agreement reached to merge the businesses of Deloitte, Plender, Griffiths & Company and Haskins & Sells in the U.S., under the name Deloitte Haskins & Sells.

1960   Touche, Niven, Bailey & Smart merges with George Touche & Co. (Britain) and Ross, Touche & Co. (Canada) to form Touche, Ross, Bailey & Smart.

1961   Issuance of American Depositary Receipts in New York by Sony and Toshiba — the first Japanese companies to sell their securities in the U.S.

1965   Fraudulent bankruptcy of the Sanyo Special Steel Company leads to changes in Japan's Certified Public Accountant Law to provide for the formation of audit corporations similar to accounting partnerships in the U.S. and elsewhere.

1968   Under the leadership of Nobuzo Tohmatsu, Founding Partner, Tohmatsu Awoki & Co. (later Tohmatsu & Co.) starts operations with 10 partners and staff in Tokyo and smaller, loosely affiliated practices in four other Japanese cities. By 1989, the firm has 800 people in its Tokyo office alone, and a network of other offices throughout Japan, as well as Japanese professionals on assignment in Touche Ross offices around the world.

1969   Adoption of the name Touche Ross & Co., at the conclusion of a decade during which mergers were completed with more than 50 other firms in the U.S. and formal associations created with national firms in 55 countries.

1972   Touche Ross Chairman Robert Trueblood chairs a committee that leads to the establishment of the Financial Accounting Standards Board — the FASB.

1975   Formal agreement is signed by which Tohmatsu Awoki & Co. become part of the Touche Ross International network.

1978   The name Deloitte Haskins & Sells is adopted.

1985   Creation of the Office of the Chairman Program (now the Global Strategic Clients Program).

1990   Merger that creates Deloitte & Touche.

1993   International firm is named Deloitte Touche Tohmatsu.

1996   Deloitte & Touche Eastern Europe divided into two organizations — Deloitte & Touche Central Europe and Deloitte & Touche CIS.

1997   Deloitte & Touche Central America is established.

2000   Deloitte Touche Tohmatsu became a founding member of the United Nations Global Compact, which seeks to promote responsible global citizenship by advancing universal values in business operations around the world.

2002   Deloitte Touche Tohmatsu’s global revenues were US$12.5 billion.

2003   A decision to not separate Deloitte Consulting allows Deloitte Touche Tohmatsu to maintain its wide and deep range of multidisciplinary capabilities.

2003   On June 1, William G. Parrett is named Chief Executive Officer of Deloitte Touche Tohmatsu. Parrett joined the organization in 1967, and became a partner in 1977.

2003   On October 1, Deloitte Touche Tohmatsu records its 10th consecutive year of annual growth, with combined worldwide revenues from its member firms totaling US$15.1 billion. Additionally, the global organization announces the launch of the new brand name “Deloitte.” The change means that the firms known in various national and global markets as Deloitte Touche Tohmatsu and Deloitte & Touche, while retaining their local legal names, will now be known by the brand “Deloitte.”

2005   On August 29, William Parrett, CEO Deloitte Touche Tohmatsu, announces the name of a strengthened Korean Deloitte member firm—Deloitte Anjin LLC, the result of a transaction between Deloitte Hana and Anjin LLC.

2005   On September 1, Deloitte Touche Tohmatsu China merges with Pan-China Schinda, the second merger in the Mainland that year following a deal with Beijing Pan-China CPA Ltd.

2005   On December 19, Deloitte Touche Tohmatsu records its 12th consecutive year of annual growth, with combined worldwide revenues from its member firms totaling US$18.2 billion, a 10.9 percent increase over 2004 revenues of US16.4 billion.

2006   Deloitte Touche Tohmatsu announces aggregate revenues of more than US$20 billion in the fiscal year ending 31 May 2006, an increase of 10 percent over 2005. It is the fourth consecutive year of double-digit revenue growth and the 13th consecutive year of continued growth.

2007   On June 1, James H. Quigley is named Chief Executive Officer of Deloitte Touche Tohmatsu, succeeding William G. Parrett. In addition, John P. Connolly is named the new Chairman of the Board of DTT, succeeding Piet Hoogendoorn.

2007   Deloitte Touche Tohmatsu announces aggregate revenues of US$23.1 billion in the fiscal year ending 31 May 2007, an increase of 15.5 percent over 2006. It is the fifth consecutive year of double-digit revenue growth and the 14th consecutive year of continued growth.