Boss Tweed is by 1871 a member of the board of directors of not only the Erie Railroad and the Brooklyn Bridge Company, but also the Third Avenue Railway Company and the Harlem Gas Light Company.

He is president of the Guardian Savings Banks and he and his confederates have set up the Tenth National Bank to better control their fortunes.

Tweed's downfall comes in the wake of the Orange riot of 1871, which occurs after Tammany Hall bans a parade of Irish Protestants celebrating an historical victory against Catholicism, because of a riot the year before in which eight people died when a crowd of Irish laborers attacked the paraders.

Under strong pressure from the newspapers and the Protestant elite of the city, Tammany had reversed course, and the march had been allowed to proceed, with protection from city policemen and state militia.

The result is an even larger riot in which over sixty people are killed and more than one hundred and fifty injured on July 12.

Although Tammany's electoral power base is largely centered in the Irish immigrant population, it also needs the city's elite to acquiesce in its rule, and this is conditional on the machine's ability to control the actions of their people, but the July riot shows that this capability is not nearly as strong as had been supposed.

Tweed had for months been under attack from the New York Times and Thomas Nast, the cartoonist from Harper's Weekly, but their campaign has had only limited success in gaining traction.

They had been able to force an examination of the city's books, but the blue-ribbon commission of six businessmen appointed by Mayor A. Oakey Hall, a Tammany man, which includes John Jacob Astor III, banker Moses Taylor and others who benefit from Tammany's actions, had found that the books had been "faithfully kept", letting the air out of the effort to dethrone Tweed.

The response to the Orange riot of 1871 changes everything, and only days afterwards the Times/Nast campaign begins to garner popular support.

More importantly, the Times has started to receive inside information from County Sheriff James O'Brien, whose support for Tweed has fluctuated during Tammany's reign.

O'Brien had tried to blackmail Tammany by threatening to expose the ring's embezzlement to the press, and when this had failed, he had provided the evidence he had collected to the Times.

Shortly afterward, county auditor Matthew J. O'Rourke had supplied additional details to the Times, which had reportedly been offered five million dollars to not publish the evidence.

The Times has also obtained the accounts of the recently deceased James Watson, who had been the Tweed Ring's bookkeeper, and these are published daily, culminating in a special four-page supplement on July 29 headlined "Gigantic Frauds of the Ring Exposed".

Tweed begins in August to transfer ownership in his real-estate empire and other investments to his family members.

The New York City Comptroller resigns shortly thereafter, appointing Andrew Haswell Green, an associate of Samuel J. Tilden's, as his replacement.

Green loosens the purse strings again, allowing city departments not under Tammany control to borrow money to operate.

Green and Tilden have the city's records closely examined, and discover money that had gone directly from city contractors into Tweed's pocket.

The following day, they have Tweed arrested.

Jay Gould, like Tweed, had become the subject of political cartoons by Thomas Nast in 1869.

In October 1871, when Tweed is held on one million dollars bail, Gould is the chief bondsman.

The exposés provoke an international crisis of confidence in New York City's finances, and, in particular, in its ability to repay its debts.

European investors are heavily positioned in the city's bonds and are already nervous about its management—only the reputations of the underwriters are preventing a run on the city's securities.

New York's financial and business community knows that if the city's credit were to collapse, it could potentially bring down with it every bank in the city.

Thus, the city's elite meet at Cooper Union in September to discuss political reform: but for the first time, the conversation included not only the usual reformers, but also Democratic bigwigs such as Samuel J. Tilden, who had been thrust aside during Tammany's elevation.

Although some at the meeting advocate lynching Tweed, the general consensus is that the "wisest and best citizens" should take over the governance of the city and attempt to restore investor confidence.

The result is the formation of the Executive Committee of Citizens and Taxpayers for Financial Reform of the City (also known as "the Committee of Seventy"), which attacks Tammany by cutting off the city's funding.

Property owners refuse to pay their municipal taxes, and a judge—Tweed's old friend George Barnard, no less—enjoins the city Comptroller from issuing bonds or spending money.

Unpaid workers turn against Tweed, marching en masse to City Hall demanding to be paid.

Tweed doles out some funds from his own purse—fifty thousand dollars—but it isn't sufficient to alleviate the crisis, and Tammany begins to lose its essential base.

Tweed had been released on one million dollars bail, and Tammany had set to work to recover its position through the ballot box.

Tweed is reelected to the state senate in November 1871, due to his personal popularity and largess in his district, but in general Tammany has not done well, and the members of the Tweed Ring begin to flee the jurisdiction, many going overseas.

Tweed is re-arrested, forced to resign his city positions, and is replaced as Tammany's leader.

Once again, he is released on bail—eight million dollars this time—but Tweed's supporters, such as Jay Gould, feel the repercussions of his fall from power.

Public indignation over Gould’s role in the Black Friday panic will force him to resign as director of the Erie in 1872.