Somewhere along the way a surveyor, or perhaps a soldier, was given the task of documenting the Spanish barracks in Baton Rouge.

A barrack, a warehouse, the kitchen - he drew them all in 1788 on a single sheet of paper, detailed and accurate.

No name is attached to this rendering, but it’s as important to the mix as the documents signed by Napoleon, Ponce de Leon and George Washington.

That last mentioned signature is somewhat strange. Maybe it’s because Thomas Jefferson’s name is more prominent with dealings with both Spain and France in his signing of the Louisiana Purchase.

But the presence of United States’ first president, indeed, weighs heavily in Spain’s Archive of the Indies in Seville.

The United States was a new country at the time Spain was administrator of the Louisiana territory. Spain even supported the young country’s fight for independence against Great Britain.

“But then Spain realized it might have a potential problem once the United States won its independence.” John H. Lawrence said. “They realized that the United States could invade Louisiana’s borders, so they drew up treaties with the Indian tribes. They were the first to recognize the tribes as sovereign nations.”

Lawrence is director of Museum Programs at The Historic New Orleans Collection, which is hosting the exhibit The Threads of Memory: Spain and the United States. The show runs through Aug. 14, and explores Spain’s first 300 years in what is now the United States.

The exhibit features nearly 140 items from the Archive of the Indies that are rarely displayed outside of Spain, including rare documents, maps, illustrations and paintings. This includes George Washington’s handwritten, signed letter.

The letter isn’t prominently placed inside its own display case. It’s simply placed in order beside other documents chronicling this story. Part of this story was the United States’ gradual growth and Spain’s natural instinct to protect its territory.

Washington learned of Spain’s treaties with the Indian nations. The idea was that if the United States encroached in Louisiana, the Indian tribes would help the Spanish defend the territory because it was part of their own.

“So, George Washington wrote this letter to the Choctaw tribe, reminding them of the agreements they already had with the United States,” Lawrence said. “He must have written two copies, because he sent this one to Spain.”

There it is, signed George Washington. The United States needed access to the Mississippi River for transporting its goods. Even more important, the United States needed that access without the burden of tariffs. Such an agreement eventually was struck between the two countries in the Pinckney Treaty, and a bigger-than-life painting of Washington commemorating that treaty hangs in this exhibit. The painting doesn’t belong to the United States but to Spain. It also is a part of the Archive of the Indies collection.

The United States had access to the Mississippi River, the same river that continues to flow through Baton Rouge, where stood the Spanish barracks. Again, though no prominent name is attached to the drawings of the barracks, the paper is just as valuable as Washington’s letter in the archives. That part of history would be lost without it.

The Spanish were known for their attention to detail. They were considered probably the world’s best at record-keeping and documentation. This was before computers, long before the concept of flash drives and gigabytes. Everything was handwritten, hand-drawn, and carefully preserved and stored in Spain. It’s now what could be considered a handful of the Archive of the Indies’ vast collection.

“It’s difficult to single out one must-see item, because all of the items on view are treasures,” Alfred E. Lemmon said. “Each piece illustrates how this region developed, and this is a once-in-a-lifetime opportunity, because Spain rarely allows these materials to travel abroad.”

Lemmon is director of the Williams Research Center at The Historic New Orleans Collection. The Collection is last of only three stops for this exhibit, the other two being the New Mexico History Museum in Santa Fe and the El Paso Museum of History in El Paso, Texas.

“Some museums didn’t have adequate exhibition space,” Lemmon said. “And European countries have guidelines on how long they will let their artifacts out of the country. For France, it’s three months. For Spain, it’s six.”

But the artifacts in The Threads of Memory have been showing outside of Spain since October.

“So, this is a very special arrangement,” Lemmon said.

Lawrence, meantime, said it is important to note that The Threads of Memory is on display in a Spanish-era building in New Orleans.

“France didn’t colonize Louisiana, because there was no silver and gold here,” Lawrence said. “Spain was given control, and it colonized the region.”

“While Louisiana is frequently identified with France, the importance of Spain and the development of Louisiana and the Gulf South is more critical than what immediately meets the eye,” Lemmon added. “When horrible fires destroyed New Orleans in 1788 and 1794, Spanish officials enacted far more stringent building codes, which protected many of the buildings you see today. They even helped protect the French language by issuing proclamations in French and in Spanish, publishing a French newspaper and encouraging the immigration of French St. Domingue and Acadian refugees.”

Once the exhibit’s run ends at The Collection, everything will be put back into place at the Archive of the Indies, where everything is treated with equal care, regardless of the signatures or lack thereof.

The Threads of Memory was organized by The Historic New Orleans Collection, Accion Cultural Espanola, the Spanish Ministry of Foreign Affairs and Cooperation and the Spanish Ministry of Culture with support from the Embassy of Spain in Washington, D.C.

The exhibit was curated by Falia Gonzalez Diaz, chief conservator at the Archive of the Indies.

“The exhibition shows a history forgotten,” Diaz said in a previously released statement. “America’s colonial past did not begin in 1607 with the founding of Jamestown but a century earlier, when Juan Ponce de Leon discovered Florida in 1523, and Spanish expeditions of exploration expanded the knowledge of the New World and its native inhabitants.”

That’s actually where this exhibit begins, with Ponce de Leon writing a letter detailing his discovery of the Island of Florida. From where he stood, Florida looked more like an island than a peninsula.

Everyone knows from their elementary school history units that Ponce de Leon wasn’t so much interested in discovering Florida as he was in finding the Fountain of Youth. But what everyone might not so handily know is that his first name was Juan. Teachers just had a way of simply identifying him as Ponce de Leon, which is exactly how he signed the letter at the start of the exhibit.

Yes, the letter is as real as George Washington’s later in the exhibit - as real as Napoleon’s signature authorizing Laurent to draw up an agreement for the Louisiana Purchase in the last gallery.

“Yes,” Lawrence said, “These documents have the actual DNA of the people who wrote them.”

The exhibition is divided into 10 sections, beginning with the early 16th century exploration and settlement of Mexico by Hern?n Cort?s and, of course, Ponce de Leon and Florida.

The show continues its journey with an overview of the establishments of the mission system and presidios in the American West and Southwest. Other sections explore the administration of Louisiana under Spain and the role of Spain in the American Revolution, which is where George Washington becomes a prominent player in the Archive of the Indies.

Firsthand accounts by Spanish explorers, mapmakers, surveyors, military personnel and other personalities detail encounters with native Americans and describe the natural landscape and its animal populations.

One noted item, a drawing of American buffalo, may not seem so unusual to the eye today. But imagine what was reeling through Spanish explorers’ minds when they first beheld the sight of a wooly herd in 1598, when the drawing was made.

“They’d never seen anything like that,” Lawrence said. “It makes you wonder what they must have thought.”

“Everything is written on paper, and they had to bring paper from Spain, because there were no paper mills in Louisiana,” Lemmon added. “People don’t realize Spain’s impact on paper because of the Moorish press. When we talk about a ream of paper, we’re using a Moorish word - ream. If the paper was no good, it couldn’t survive the hardship.”

But the paper was good, and it did survive. It’s here in this exhibit, bearing renderings of maps documenting the gulf coast, and later the Louisiana territory and American West. The maps begin with line drawings and evolve into large, colorful illustrations as the exhibit progresses.

And in the spirit of the Spanish’s attention to detail, terrain is noted in different regions. Even specific buildings are detailed in smaller maps of communities and townships.

“When Spanish officials came over, they could look at these maps and know exactly where everything was in a town with having never been there,” Lawrence said.

Still, one of the most striking images isn’t a map, and the edges of the thick paper on which it was created are uneven. In fact, it appears to have been torn from a larger sheet, which makes it even more intriguing, its brownish shade conjuring thoughts of old treasure maps.

Perhaps that’s because the hand-drawn image shows a wooden ship with sails. Color was added with what seems to be pigment created from clay.

“This is a drawing of La Salle’s ship La Belle heading for the mouth of the Mississippi River,” Lawrence said. “It ended up in Texas.”

That’s as in the explorer Rene-Robert Cavelier sieur de La Salle, who sailed on the ship from France on an expedition in 1684 to establish a colony in Louisiana. The piece was created in the year of La Salle’s expedition.

Still, La Salle’s involvement is specific to Louisiana in this exhibition, as are the Pinckney Treaty that allowed the United States access to the Mississippi River, the maps of the Gulf Coast and the map of the Vieux Carre that made up the heart of New Orleans on the river’s crescent.

And, of course, the Spanish Barracks in Baton Rouge.

Drawn in careful detail and perfectly preserved in the Archive of the Indies so as never to be forgotten.