While the condition of affairs at the Isthmus was thus in an unsatisfactory condition, the authorities were constantly in dread of invasion from foreign powers. Early in the year 1561 two caravels arrived with intelligence that a large fleet had sailed from England for America, and with orders that preparations be made for a stout defence. The treasure on board the ships lying in harbor was quickly removed and secreted on shore, and no vessels were allowed to leave port until the arrival of the convoy fleet from Spain under the adelantado Pedro Menendez. It is not recorded that on this occasion the English made any attempt to land on the shores of Tierra Firme, but four years later, the monarchs of England and Spain being then on friendly terms, one Captain Parker touched at the coast of Darien ostensibly for the purpose of trading with the natives. An armed flotilla was despatched against him, but the captain refused to depart, and when attacked not only repulsed his assailants, but captured one of the enemy's squadron.[XXII‑36] [Sidenote: FEAR OF PIRATES.] Although, as will be told in the next chapter, the Isthmus was several times invaded by English adventurers between 1572 and 1596, it was not until near the end of the century that any really effectual measures were completed for its protection. On the 2d of May 1574 the king wrote to the audiencia of Panamá, that he had information of many privateering expeditions then being fitted out with the intention of proceeding to the Indies. In 1580 three ships of war were stationed on the coast to guard against corsairs and it was ordered that criminals be delivered over to serve as oarsmen on board these vessels. In 1591 a more powerful fleet was sent to the West Indies and fortifications ordered to be erected at the town of Cruces and other points on the Isthmus. At this date Panamá alone could put into the field eight hundred Spanish infantry and fifty horse. Four years later a site was selected for a fort at the mouth of the Chagre river. Finally in 1597, when the news of Drake's last expedition had thoroughly roused the king to a sense of the danger, mechanics were sent out from Spain to hasten the completion of the defences, and it was ordered that the cost be defrayed from the royal treasury.[XXII‑37] Panamá was assailable from three different points: from Nombre de Dios, whence it could only be reached through the mountain passes of Capira, where a small band of resolute men could hold an army in check; from Acla, fourteen leagues east of Nombre de Dios, where men of war had formerly anchored; and by way of the Rio Chagre, which was navigable for large boats as far as Cruces, the road thence to Panamá presenting no serious obstacle to an invading force.[XXII‑38] CHAPTER XXIII. DRAKE AND OXENHAM'S EXPEDITIONS. 1572-1596.