It's probably best to begin by bursting perception and exposing the naked truth: Rigoberto's is not owned by someone named Rigoberto. Eriberto does not run the show at Eriberto's. There is no Humberto at Humberto's and no Roberto at Roberto's.

"It's just a name," said Maria Estrada, owner of Roberto's Authentic Mexican Food in north Phoenix. "I don't have a father or a husband or even a son with that name."

The sheer number of 24-hour Mexican takeout spots with "-berto's" in their name is no coincidence. But it's not as if having a first name with the -berto's suffix compels you to make overstuffed burritos and fry up batches of rolled tacos.

Instead, the restaurants' names come from good old American marketing strategy. They've turned -berto's into a brand.

The -berto's saga begins in California with a real -berto. Roberto Robledo, along with his wife, Dolores, opened Roberto's Taco Shop in San Diego in 1964. In the 1980s, according to the company's Web site, Roberto's opened new locations.

Over time, said Estrada, who lived in California during the birth of the -bertos, the original family members extended the concept under the name Alberto's. The restaurants were yellow and red, had impossibly long menus and were very popular.

They soon spawned imitators: Aliberto's, Adiberto's and Loberto's, among others.

So when the Tenorio family decided to open its 24-hour takeout spot in San Diego in 1988, it made sense that they chose to name it Filiberto's, after the brother whose name conjured up thoughts of machaca burritos.

"It ended with -berto's," said Nancy Tenorio, office manager for the Filiberto's corporate office in Arizona. The state's first Filiberto's opened in Mesa in 1993. It had the familiar yellow and red paint scheme, with the name printed in flowing red cursive letters. Other Filiberto's locations soon followed.

"A lot of people say, 'Everybody's -berto,' " Tenorio said, "but everybody knows who's first." At least in Arizona.

Her uncle, the chain's namesake, lives in Mexico now, Nancy Tenorio said.

But Filiberto Tenorio-Quintero sees it as a compliment that so many other restaurants opened using the -berto name, Tenorio said, showing that the family had successfully imported the concept from California.

Ariadna Armenta, who opened Dagoberto's in northwest Phoenix in 2005, said the tag "seemed like the signature of fast food" in Phoenix. Her restaurant, now closed, took the name from one of her original investors, she said.

It was the same story with Roberto's, in a Shell gas station on Union Hills Road in Phoenix, according to Estrada. She said a man named Roberto was supposed to invest in the takeout place. The deal was never struck, "but I stuck with the name," she said.

Aside from the concept, the Phoenix location has no official relationship to the original Roberto's in California.

Humberto's Mexican Food, 35th Avenue and Cactus Road, took its name from the franchise in San Diego, said owner Jose Diaz. "He's a man in San Diego," Diaz said, when asked who Humberto is.

A check of paperwork on file with the state of Arizona doesn't show any other -berto's restaurants owned by people actually named -berto.

Eriberto's in Phoenix is owned by a Felipe. Rigoberto's in Mesa is operated by a Sergio. And a Juan is on file as being in charge at Rolberto's in Glendale.

Calls to various -berto's restaurants elicited names of different managers and owners, suggesting that operators of these restaurants flip over faster than a quesadilla.

Same with the names. The owner of a restaurant listed as Polberto's Mexican Food in Sun City was confused when asked who Polberto was.

"Hell if I know," Jose Alvarez said. "This restaurant is called Don Jose."