Lima was a great city of the New World, capital of the opulent kingdom of Peru, which included over a hundred Spanish towns and villages. The city was the home of the viceroy, an archbishop, a university, and many splendors.

Catalina went to work for a grand merchant of the city, who was very satisfied with her services. However, the merchant became concerned because there were two young ladies in the house, his wife's sisters, and she became accustomed to frolicking with them. One in particular had taken a fancy to her. One day the merchant caught her with her head up the girl's skirt and fired Catalina on the spot.

Abruptly she found herself homeless and with no friends or money. Six companies of soldados were being raised to fight in Chile and she joined on, receiving immediately an allotment of nearly three hundred pesos.

The soldiers shipped out to Concepción in Chile, a port that goes by the name "the noble and the loyal" and is large enough to have its own bishop. There, to her surprise, she met her brother, Miguel de Erauso. She had four brothers and four sisters, and she had never met Miguel. Naturally Catalina did not let him know that she was in any way related to him, much less his sister. When he found out that her name was also Erauso and the area she was from, he took her as a friend. She spent several idyllic years in Concepción. The good times came abruptly to an end when her brother caught her visiting his mistress and they fought. She ended up being banished to Paicabí, a miserable outpost where war was constant with the indios.

There was nothing to do in Paicabí except eat, drink, and fight. They even slept in their armor. Finally a force of five thousand was gathered to meet an indio army of much greater size. They engaged them on open ground near Valdivia, which the indios had sacked. They gained the upper hand and slaughtered many of the indios, but when the victory was nearly complete, indio reinforcements arrived and they were driven back. They killed many of her men, including her own lieutenant, and rode off with the company flag.

When she saw the flag being carried off, she rode after it, with two other horse soldados at her side. They chased the flag carrier through an almost solid wall of indios, trampling them under their horses' hooves and slashing them with their swords. They took wounds in return, and one of Catalina's companions took a spear in the throat. He went down but the remaining two of them hacked their way to the indio cacique who had stolen their company's standard. As she reached him, her companion was dragged from his horse by a dozen indios. She had taken a painful blow to her leg, but she surged on. She came up behind the cacique and slashed him in the back of the neck, grabbing the standard as he went down. She then turned to fight her way back.

Catalina spurred her horse on, trampling, killing, and slaughtering more indios than she could count. She took three arrows in the back and a gash from a spear in her left shoulder. When she broke out of the multitude of indios, she raced across to where her own men were assembled. They cheered as she brought back the company colors. Her horse had taken a mortal wound but drove on as if it had wings. It went down when she reached her own lines, and she went down with it.

Her wounds were well tended to, and she received the honor of being made a lieutenant. Catalina served five more years in that rank and fought many more battles. She fought and captured a Christian indio cacique named Francisco, who had done much damage to their forces and carried off much booty. He was said to be one of the richest indios in Chile. After she knocked him from his horse, he surrendered to her and she strung him up from the nearest tree.

The impetuous hanging of the rich indio outraged the governor, and she found herself sent back to Concepción. This was actually good fortune, but Chance had always made her life miserable, turning each piece of luck into a disaster.

Her fall from respectability began when she was frequenting a gambling house with one of her fellow officers. A small misunderstanding arose between her and her companion, who accused her of cheating and announced in a loud voice that every word out of her mouth was a lie. Catalina drew out her dagger and plunged it into his chest. Things became more complicated when the local judge attempted to arrest her on the spot. She drew her sword and slashed him, then as a dozen men in the room charged her, she backed to the door, holding them back with her sword. Outside she ran for the sanctuary of the cathedral.

The governor and his constables were forbidden to arrest her on church grounds. She stayed in the church for six months when one of her friends, a lieutenant by the name of Juan de Silva, came to her and asked her to be his second in a duel to be fought near midnight that very night. Assured that this was no trap to lure her from the church, she agreed to accompany him. Dueling had been forbidden by the governor, and they wore masks to hide their identity.

She stood by, as was the custom for seconds, while her friend dueled with the other man. When she saw that he was being bested and about to be killed, she drew her sword and joined the fight. The other man's second soon engaged her, and her point went through a double thickness of leather and into his left breast near the nipple. As he lay dying, she discovered to her horror that the man she had mortally wounded was Miguel de Erauso, her own brother.

Catalina left Concepción, with horse and weapons, and went onto Valdivia and Tucumán.

She set out along the coast, suffering greatly, first from thirst and second from a lack of food. She fell in with two other soldados, deserters both. As the leagues unfolded beneath them, they went over mountains and across deserts, driven by hunger and desperation, never seeing another human except an occasional indio who fled before them. They killed one of the horses for food, but found it to be nothing more than hide and bones. But they continued to press on, league after league, over three hundred in all, until they ate the other horses and her two companions fell and never got up. When her last amigo had dropped to the ground, sobbing that he could not get up, she left him, taking eight pesos from his pocket.

She was overcome by fatigue and hunger when two indio riders found her. Taking mercy upon her, they carried her to the cattle estancia of their mistress. The woman was a mestizo, the daughter of a Spaniard and an india woman. She restored Catalina to health and began to rely upon her in running her ranch. There were few Spaniards in the region, and she soon proposed that Catalina marry her daughter.

She had played a bit with the daughter, no more than touching her in private places and kissing her, but in truth, she was as ugly as the devil himself, quite the opposite to Catalina's own preference for pretty faces. She had to agree to the marriage, but she managed to delay it for two months. She was finally forced to flee in the night, taking the proposed dowry with her.

Catalina was again arrested for murder after other adventures, and this time her reputation as a swordsman, gambler, and rogue had spread to the point that she knew she would soon be dispatched to her Maker.

Seeking the protection of the Church a final time with a constable wanting to drag her to the gallows, Catalina confessed to him that she was, in fact, a woman and had spent her early life in a convent.

After much thought, he had Catalina examined by two old women, who confirmed not only her sex, but the fact that she was still a virgin.

Rather than the recriminations she had expected from her confession, the news that the notorious Sancho de Erauso was actually a woman soon made its way across the sea to Europe.

Catalina found herself on a ship again, this time taking her back to Spain—not to a prison, but for an audience with the king. And after that to Rome to see the pope.