Mendoza had guarded against rival expeditions from his own territory, and so soon as he knew that Friar Marcos had succeeded in his quest, he took precautions to prevent the news of the discovery from reaching other portions of the New World. His chief fear, probably, was lest De Soto, who had recently received a license to explore the country between the Rio de las Palmas, in the present Texas, and Florida,[43] might direct his expedition toward the western limits of his territory, if he should learn of the rich prospects there. Although Mendoza probably did not know it, De Soto had sailed from Habana in May, 1539, and in July, sending back his largest ships, he began the long march through the everglades of Florida, which was to end in the Mississippi. Mendoza, with all the formality of the viceregal authority, ordered that no vessel sailing from New Spain should touch at any port in the New World on its way back to the home peninsula, and this notice was duly served on all departing shipmasters by the secretaries of the viceroy. By the middle of November, however, despite all this care, a ship from Vera Cruz sailed into the harbor of Habana. The master declared, on his oath, that he had been forced to put in there, because sickness had broken out aboard his vessel soon after the departure from New Spain and because he had discovered that his stock of provisions and water was insufficient for the voyage across the Atlantic. Curiously enough, one of the crew, possibly one of those who had been seized with the sickness, had in his possession some letters which he had been asked to deliver to Hernando De Soto, in Habana. Apparently the agent or friend of De Soto living in Mexico, one Francisco de Billegas, did not know that the adelantado had left Cuba, although he had arranged to have the letters carried to Spain and given to the representative of the adelantado there if De Soto was not found at Habana. De Soto had taken care that his interests should be watched and protected, in Spain as well as in the New World, when he started on his search for the land of wealth north of the Gulf of Mexico, the search on which Ayllon and Narvaez had failed so sadly.