Nearly every great city has been impacted by a great fire.

Rome had the 64 A.D. fire that the Emperor Nero would try to blame on early Christians. London had the 1666 conflagration that led to the rebuilding of St. Paul’s Cathedral with its now iconic dome by Christopher Wren.

Chicago had the 1873 blaze long blamed on Mrs. O’Leary’s cow.

Pittsburgh, too, had a great fire. The 1845 fire would get credit from some historians for driving Pittsburgh’s growth and turning into the industrial powerhouse it would become in the latter half the 19th century.

By 1840, Pittsburgh had more than 21,000 residents, according to U.S. Census figures, and by 1850 its size would more than double to 46,000 residents. That growth was largely because of industrialization, with iron and glass manufacturing, as well as milling and textile making, leading the way.

As with many cities in the 19th century, Pittsburgh was growing haphazardly and unevenly, with frame boarding houses close by mansions for the city’s elite.

And in April 1845, that would contribute to the disaster about to unfold.

Ida Adams, writing in a 1942 edition of Western Pennsylvania Historical Magazine about the fire, would tell the story of how the fire began.

“We do not know her name, but living in a small frame house at Second and Ferry streets was a woman who has been classed with Mrs. O'Leary and her cow of Chicago fire fame,” Adams wrote. “We can picture her even now as she carried out the big black iron kettle and set it up in the yard near the wall of the ice house next door on Ferry Street.”

Sparks from that fire would set the ice house next door ablaze, and the fire would spread from there. The frame homes surrounding the ice house offered ready fuel for the fire, as J. Heron Foster explained in his pamphlet, “A Full Account of the Great Fire at Pittsburgh, on the Tenth Day of April, 1845.”

Foster opens in florid, mid-19th century style.

“It is impossible for any one, although a spectator of the dreadful scene of destruction which was presented to the eyes of our citizens on the memorable tenth of April, to give more than a faint idea of the terrible, the overwhelming calamity which then befel (sic) our city, destroying in a few hours the labor of many years, and blasting suddenly the cherished hopes of hundreds — we may say thousands — of our citizens, who, but that morning, were contented in the possession of comfortable homes and busy workshops,” he wrote.

“The blow was so sudden and unexpected as to unnerve the most self-possessed, and few witnessed more than the destruction of their own property and that in the immediate neighborhood, whilst engaged in vain efforts to save it. Our work is therefore necessarily more of a statistical than descriptive nature, designed to preserve for future reference the various incidents of the conflagration, which must else have passed from the memory as rapidly as the traces of our disaster are now disappearing before the magic wand of industry and enterprise.”

The decision to leave a fire unattended, even for a second, was especially careless on that day, April 10, 1845, because the city had gone weeks without rain and high winds had been plaguing the area throughout the week.

It would result in a truly devastating fire.

With frantic effort, people were able to save Third Presbyterian Church on Ferry Street, which many credited with stopping the fire’s spread in that direction. But that was one of only a few victories, with one witness estimating between 1,000 and 1,200 houses were destroyed, in addition to numerous businesses and industrial concerns.

“All this happened between twelve and two o'clock, at which time burning pieces of wood like flaming torches were being scattered by the wind as far as half a mile away, setting up so many fires that there was no chance of stopping them,” Adams wrote. “Every man who had been fighting the further spread of the fire now hurried home to save what he could.”

Foster’s pamphlet gives vivid descriptions of different scenes, tracing the fire from beginning to end.

“The fire extended along the rows of wholesale commission and forwarding, iron and grocery warehouses on Water street with fearful rapidity — property of every description, boxes, bales, bags, were hastily removed from the burning buildings, to the wharf, but the intense heat, the darting flame and the falling sparks fired the mass and the destruction extended to the very water's edge, the steamboats in port at the time dropping down the river as far as the mouth of Saw Mill Run, on the opposite side of the Monongahela river,” Foster wrote.

There were a number of problems that hindered efforts to fight the blaze. Most prominently, there were only two water mains in the city, meaning there wasn’t enough water pressure.

Donald E. Cook Jr. wrote in a 1968 issue of Western Pennsylvania Historical Magazine, about the efforts of the volunteer fire companies.

“At this time there were six volunteer fire companies in Pittsburgh (Eagle, Allegheny, Vigilant, Duquesne, Neptune, Niagara) and four in Allegheny (Uncle Sam, Washington, William Penn, Union Hose Company),” Cook wrote. “Most of these were involved in fighting the fire; the Vigilant lost its engine house and most of its equipment, and the Neptune was lost trying to save the Third Presbyterian Church. All of the Pittsburgh companies lost a considerable part of their hose.”

One reason was the lack of water. Cook quotes an eyewitness who saw firefighters preparing to pump and then seeing only a “sickly stream of muddy water” emerge from the hose.

The burned district made up about a third of the city’s area and accounted for as much as two-thirds of its wealth.

In his autobiography, Samuel Young, who would serve as a general during the Spanish-American War and eventually be the Chief of Staff of the Army, wrote that the fire, which happened when he was 5, was devastating, but there was still energy left.

The losses were immense, totaling millions of dollars at the time, but the city wasn’t destroyed. It was hurt, and it needed help, but it wasn’t finished.

That help came, and it came quickly, and before long Pittsburgh was again thriving.

Cook cites a late 19th century observer in his article.

“An observer, distant in both miles and time, in 1898 remarked that the fire ‘proved in the end, as in all such cases, a real benefit to the city, although it meant the ruin of individuals,’” he wrote. “New business-men replaced old, and as the initial shock wore off, capital flowed in and ‘the city entered upon a remarkable era of development, despite the depressing effects of the tariff of 1846 upon this great manufacturing center.’”

In the years and decades after the fire, its memory remained strong, and it was commemorated each year, even being the subject of a ceremony in April 1936, less than a month after the devastating St. Patrick’s Day flood.

But by the time Cook was writing, and even more so now, the fire had largely been forgotten. It reshaped Pittsburgh, but it has slipped out of the public consciousness.

“The Great Fire has become one of those past events that are put away as a relic of a bygone era, as a piece of not very important history,” Cook wrote. “For the people in Pittsburgh that bright warm Thursday in 1845, however, the fire was a very real thing, and one they never forgot.”