The land now called Brazil was claimed by the Kingdom of Portugal in April 1500, on the arrival of the Portuguese naval fleet commanded by Pedro Álvares Cabral. The Portuguese encountered Indigenous nations divided into several tribes, most of whom shared the same Tupi–Guarani languages family, and shared and disputed the territory. But the Portuguese, like the Spanish in their North American territories, had brought diseases with them against which many Indians were helpless due to lack of immunity. Measles, smallpox, tuberculosis, and influenza killed tens of thousands.