With its merger with Norton Rose going live on Monday, Fulbright & Jaworski becomes the latest Am Law 100 firm to target global growth by inking a merger deal with a leading London firm.

The combined firm, Norton Rose Fulbright, is now the third largest in the world by attorney head count with 3,800 lawyers in more than 50 cities, according to sibling publication Texas Lawyer. Houston-based Fulbright will drop the name of late founding partner Leon Jaworski, who was once the youngest lawyer in the Lone Star State.

Norton Rose’s own exponential growth in recent years helped turn the firm into the colossus it is today. In 2010, Norton Rose picked up Canada’s Ogilvy Renault and South Africa’s Deneys Reitz, while merging with Calgary-based energy shop Macleod Dixon the following year.

The Am Law Daily decided to look back at The American Lawyer’s Am Law 100 list from 1999—just before Magic Circle firm Clifford Chance clinched the first large transatlantic tie-up with Rogers & Wells—to see which U.S. firms chose to expand abroad by staking out a merger partner in London.

London, which is battling New York and Hong Kong to remain the world’s top financial capital, often acts as a gateway to international expansion elsewhere.

“There’s a saying that if you buy in London, you get Europe for free,” says Ward Bower, a longtime law firm M&A expert and principal with legal consultancy Altman Weil who has helped broker several transatlantic mergers.

The U.S. legal market, which is larger both financially and geographically than the United Kingdom, has watched many of its largest firms spend most of the past two decades consolidating regionally. The larger U.K. firms, most of which make the bulk of their money domestically in London and thus don’t have a financial need to expand elsewhere in the British Isles, having focused their expansion efforts on the old markets of the British Empire in Asia, Africa, and the Middle East.

Bower says that within the past 10 years, many large firms in the U.K. and United States have begun to see their dual merger tracks coalesce. Of course, expanding into London with an eye toward becoming a global legal player isn’t easy.

“It’s just too hard to build from scratch in London,” adds Bower, noting that the cost of recruiting lateral partners and obtaining office space in London’s Old City neighborhood—where almost all the country’s major firms are based—can quickly become prohibitive. And during his career, Bower’s seen some U.S. firm leaders misunderstand what comes with London calling.

“Some go over there for vacation and think they’ve got it all figured out,” says Bower, “but the London legal market is much more complex than New York, both in terms of [law firm] volatility and a wide disparity in profitability.”

While many international mergers in recent years have come in Canada and the Asia-Pacific region—Australia has been a particularly hot target for acquisitive-minded British firms—Bower says that London will remain a top destination for U.S. firms as a result of the path the city provides to other global markets.

Listed below are all of the transatlantic mergers of note since 2000 involving U.K. firms and their U.S. peers, according to data provided by Bower, who works closely with former Clifford Chance managing partner–turned-adviser Tony Williams of London’s Jomati Consultants. (Altman Weil has a strategic alliance with Jomati—the two consultancies also track U.S. and U.K. firm mergers on their websites.)

Not all merger discussions were successful. Fried, Frank, Harris, Shriver & Jacobson and London’s Ashurst broke off tie-up talks in 2003, while big British firm SJ Berwin has mulled potential mergers with Orrick, Herrington & Sutcliffe and Proskauer Rose, with talks with the later two firms ending in 2010. (SJ Berwin is now reportedly in advanced merger talks with Asia-Pacific legal giant King & Wood Mallesons and Ashurst is poised to complete a full merger with its Australian legal arm.)

Nine Am Law 100 firms that existed in 1999 have since gone defunct—they are also listed below—while another 14 have gone on to finalize transatlantic merger deals. Eleven of those firms are now among the top 40 largest firms in the world by attorney head count, according to The American Lawyer‘s most recent Global 100 list.

2000: Clifford Chance and New York’s Rogers & Wells became the first major firms to ink a transatlantic union, although The American Lawyer would subsequently report in depth on the marriage’s rocky start and lingering integration issues. The landmark deal involved the absorption of Germany’s Punder, Volhard, Weber & Axster, which was followed by Magic Circle rival Freshfields inking its own megamerger in 2000 with German firms Bruckhaus Westrick Heller Lober and Deringer Tessin Herrmann & Sedemund.

2000: Dechert—then known as Dechert, Price & Rhoads—announced its merger with London’s Titmus Sainer Dechert after a six-year affiliation agreement between both firms. Chambers reported that prior to the alliance deal, the firm formerly known as Titmus, Sainer & Webb had been struggling with a downturn in the British real estate market.

2001: Reed Smith joined the growing London party by combining with 60-lawyer Warner Cranston, giving the Pittsburgh-based Am Law 100 firm its first office overseas. The deal was prelude to a larger London merger involving Reed Smith five years later.

2002: Mayer Brown was the next Am Law 100 firm to take the transatlantic plunge, merging with London’s Rowe & Maw. The combined firm, which dropped the Rowe & Maw from its shingle in 2007, acquired Hong Kong’s Johnston Stokes & Master in early 2008.

2002: Shook, Hardy & Bacon entered the London market through a merger with 10-lawyer IP and commercial litigation shop Arnander Irvine & Zietman.

2003: Jones Day, a present day legal giant, became the sixth-largest firm in the world (it’s now fourth when measured by attorney head count) following its merger with 150-lawyer London firm Gouldens.

2005: The New Year’s Day merger between the U.K.’s DLA, Chicago-based Piper Rudnick, and San Diego–based Gray Cary Ware & Freidenrich helped make DLA Piper into what is now the world’s largest firm by attorney head count. DLA crossed the 4,000-lawyer mark by absorbing its 700-lawyer Aussie arm DLA Phillips Fox in 2011.

2005: K&L Gates’s merger mania began when predecessor firm Kirkpatrick & Lockhart combined with London’s Nicholson Graham. Since then, it has picked up regional U.S. firms based in Chicago, Charlotte, Dallas, and Seattle, while announcing a deal Down Under in 2012 with leading Australian firm Middletons, according to our previous reports.

2006: Reed Smith hit the 1,300-lawyer mark after announcing its merger with London’s Richards Butler, according to a story at the time by sibling publication The Legal Intelligencer. Reed Smith, which now has roughly 1,500 lawyers, would need another year before it absorbed Richards Butler’s Hong Kong affiliate.

2009: McGuireWoods entered London through its merger with 36-lawyer local shop Grundberg Mocatta Rakison. While small in the M&A sense, the deal brought McGuireWoods a high-profile client in Elin Nordegren, the ex-wife of golfing star Tiger Woods. Nordegren’s twin sister, Josefin Lonnborg, worked at Grundberg Mocatta and is now a corporate associate in McGuireWoods’s London office. Not surprisingly, McGuireWoods represented Nordegren in her high-profile divorce from Woods.

2010: After months of talks aimed at clinching the “first major transatlantic merger of globally oriented equals,” according to our previous reports, the tie-up between Hogan & Hartson and London-based Lovells creating Hogan Lovells officially went live in May. By rapidly expanding its global footprint from its Washington, D.C., roots, Hogan’s fate contrasted that of former Beltway rival Howrey, according to a 2011 story by Washingtonian.

2010: The same month that Hogan Lovells was formed, the firm formerly known as Sonnenschein Nath & Rosenthal announced its own transatlantic merger with London’s Denton Wilde Sapte. The new firm, subsequently called SNR Denton, would change its name again to Dentons in 2013 after announcing a three-way merger in late 2012 with Canada’s Fraser Milner Casgrain and European firm Salans.

2011: Squire Sanders—then Squire, Sanders & Dempsey—saw its own transatlantic tie-up with London-based Hammonds go live on January 1, 2011. The addition of the nearly 500-lawyer firm helped Squire Sanders cross the 1,000-lawyer barrier, although the British firm’s legacy Hong Kong office opted out of the merger and chose to join SNR Denton instead. (Squire Sanders dropped the Dempsey from its name in 2012.)

2013: The merger between Norton Rose and Fulbright goes live on June 3, with Latin American expansion for the combined firm looming on the horizon.

Four mergers between U.S. and U.K. firms since 2000 do not appear on the breakdown above. They are the 2008 union of Edwards Angell Palmer & Dodge and London’s Kendall Freeman; the 2003 merger between Faegre & Benson and 30-lawyer London firm Hobson Audley Hopkins & Wood; and the 2000 tie-up between Steptoe & Johnson and London telecommunications boutique Rakisons.

Steptoe, Faegre & Benson, and Edwards Angell were not Am Law 100 firms in 1999. Faegre entered The Am Law 100 in 2012 following its merger with Indianapolis-based Baker & Daniels, while Edwards Angell is now called Edwards Wildman Palmer after combining with a Chicago firm in 2011.

Lastly, there is the 2002 tie-up between New Haven, Connecticut–based Bergman, Horowitz & Reynolds and London’s Withers, creating one of the world’s largest private client shops. Withers’s U.S. arm is called Withers Bergman. The firm’s London-based parent recently called off merger talks with London’s Speechly Bircham, according to U.K. publication Legal Week.

As for the firms that made The American Lawyer’s Am Law 100 list in 1999 that have since gone bust, they are as follows: Arter & Hadden, Brobeck, Phleger & Harrison, Coudert Brothers, Dewey & LeBoeuf, Graham & James, Heller Ehrman, Howrey, Jenkens & Gilchrist, and Testa, Hurwitz & Thibeault.