Impregnable Quadrilateral (golf’s four major events)

American golfer Bobby Jones (1902-1971) won four major golf tournaments in a single calendar year—the United States Amateur Championship, United States Open, British Amateur and British Open. Winning four major tournaments in golf (and also in tennis) is now known as the “grand slam.”
 
New York (NY) Sun sportswriter George Trevor (1892-1951) wrote on June 2, 1930:
 
“Atlanta’s first citizen, like Napoleon before him, has stormed the supposedly impregnable ‘quadrilateral.’ Bob is the first golfer in all history to win the four major championships—American open, American amateur, British open and finally the British amateur.”
 
Trevor wrote in a September 1930 column that he was borrowing from the military term of “Quadrilateral fortresses.” The term “impregnable quadrilateral” is still used, although less frequently than “grand slam.”
 
   
Wikipedia: Grand Slam (golf) 
The Grand Slam in professional golf is winning all of golf’s major championships in the same calendar year.
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The term “Grand Slam” was first applied to Bobby Jones’ achievement of winning the four major golf events of 1930: The Open Championship, the U.S. Open, the U.S. Amateur and the British Amateur. When Jones won all four, the sports world searched for ways to capture the magnitude of his accomplishment. Up to that time, there was no term to describe such a feat because no one had thought it possible. The Atlanta Journal’s O. B. Keeler dubbed it the “Grand Slam,” borrowing a bridge term. George Trevor of the New York Sun wrote that Jones had “stormed the impregnable quadrilateral of golf.” Keeler would later write the words that would forever be linked to one of the greatest individual accomplishments in the history of sports:
 
This victory, the fourth major title in the same season and in the space of four months, had now and for all time entrenched Bobby Jones safely within the ‘Impregnable Quadrilateral of Golf,’ that granite fortress that he alone could take by escalade, and that others may attack in vain, forever.
 
Wikipedia: Bobby Jones (golfer)
Robert Tyre “Bobby” Jones Jr. (March 17, 1902 – December 18, 1971) was an American amateur golfer, and a lawyer by profession. Jones founded and helped design the Augusta National Golf Club, and co-founded the Masters Tournament.
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Jones is most famous for his unique “Grand Slam,” consisting of his victory in all four major golf tournaments of his era (the open and amateur championships in both the U.S. & the U.K.) in a single calendar year (1930).
 
Wikipedia: Quadrilatero
The Quadrilatero (English: Quadrilateral, for greater specificity often called the “Quadrilateral fortresses”) is the traditional name of a defensive system of the Austrian Empire in the Lombardy-Venetia, which connected the fortresses of Peschiera, Mantua, Legnago and Verona between the Mincio, the Po and Adige Rivers. The name refers to the fact that on a map the fortresses appear to form the vertices of a quadrilateral. In the period between the end of the Napoleonic Wars and the Revolutions of 1848, they were the only fully modernized and armed fortresses within the Empire.
 
Old Fulton NY Post Cards
2 June 1930, New York (NY) Sun, pg. 28, col. 3:
Bobby Jones Attains His Goal
Atlantan Is First Player to Win Golf’s Four Major Titles
By GEORGE TREVOR.
Golf’s latest citadel has fallen before the hickory bludgeon and steel blade of Sir Robert Jones, slayer of dragons which lurk in bunker and jungle rough.
 
Atlanta’s first citizen, like Napoleon before him, has stormed the supposedly impregnable “quadrilateral.” Bob is the first golfer in all history to win the four major championships—American open, American amateur, British open and finally the British amateur.
 
Old Fulton NY Post Cards
5 June 1930, Jamestown (NY) Evening Journal, “Sportorials: The Stars Said That Bobby Jones Should Win,” pg. 23, col. 1:
Atlanta’s first citizen, like Napoleon before him, has stormed the supposedly impregnable “quadrilateral.” Bob is the first golfer in all history to win the four major championships—American open, American amateur, British open and finally the British amateur.
 
12 September 1930, Beatrice (NE) Daily Sun, “This Game of Golf” by O. B. Keeler, pg. 8, col. 3:
Bobby, having already done something this year that nobody else ever has matched, in winning the British Amateur, the British Open, and the United States Open championships, now has the chance to entrench himself within the Impregnable Quadrilateral of Golf by doing something that nobody else probably ever will do.
 
Old Fulton NY Post Cards
16 September 1930, New York (NY) Sun, “Merion’s Vivid Two-Shotters” by George Trevor, pg. 34, col. 3:
Now Jones returns to twice-trodden ground, the eyes of the whole golf world upon him, as he essays to storm the hitherto impregnable quadrilateral—attempts to win golf’s four major titles in one calendar year.
 
In military significance, the term “quadrilateral” refers to four fortresses mutually supporting one another—Mantua, Peschiera, Verona and Legnano on Lombardy’s plain forming the classic example. The Emperor Napoleon II broke the Italian Quadrilateral at Solferino; the Emperor Jones may crash the Anglo-American quadrilateral at Merion net week.
 
26 September 1930, State-Times (Baton Rouge, LA), “Mental Hazard Bother Jones In Big Tourney” by O. B. Keeler (AP), pg. 19, col. 3:
The big opponent of Bobby Jones is not one of the three other fine competitors left in the field. It’s a giant, pale horseman, riding behind him, whenever he makes a shot. It is the specter of the fourth championship, on his trail. It is the most tremendous hazard that ever dogged a potential world champion of all time, as Bobby goes out to play for the title that entrenches him forever within the “impregnable quadrilateral” of golf.
   
18 November 1930, Bellingham (WA) Herald, “Keller, Associated Press Sports Writer, Pays Glowing Tribute To Bobby Jones, the Golfer, the Man” by O. B. Keeler (AP), pg. 11, cols. 2-3:
In the closing year, 1930, he had accomplished the impossible—the grand slam of golf—by winning all four major titles; he had flung an incomparably brilliant escalade into the impregnable quadrilateral of golf, where his record stands safely entrenched forever. For no one will ever do it again.
 
Twitter
Rick Young
‏@RickSCOREGolf
. @TheMasters @usopengolf champion @JordanSpieth half way to modern day Impregnable Quadrilateral #GrandSlam
5:13 PM - 23 Jun 2015
 
Twitter
Oliver Brown
‏@oliverbrown_tel
The holy grail, the impregnable quadrilateral. My piece on Serena and the Grand Slam http://www.telegraph.co.uk/sport/columnists/oliver-brown/11704796/Wimbledon-2015-Williams-aims-to-supersede-the-Serena-Slam-by-emulating-the-achievement-of-Steffi-Graf.html …
5:06 AM - 29 Jun 2015