The year 1492 also marked the arrival of Christopher Columbus in the New World, during a voyage funded by Isabella. Columbus's first voyage crossed the Atlantic and reached the Caribbean Islands, beginning the European exploration and conquest of the Americas, although Columbus remained convinced that he had reached the Orient. Large numbers of indigenous Americans died in battle against the Spaniards during the conquest, while others died from various other causes. Some scholars consider the initial period of the Spanish conquest— from Columbus's first landing in the Bahamas until the middle of the sixteenth century—as marking the most egregious case of genocide in the history of mankind. The death toll may have reached some 70 million indigenous people (out of 80 million) in this period, as diseases such as smallpox, measles, influenza, and typhus, brought to the Americas by the conquest, decimated the pre-Columbian population.