Who did Hercules have 51 sons with?

King Thespius had 50 daughters and wanted Hercules to impregnate them all. Hercules, who went hunting with King Thespius each day, was unaware that each night's woman was different (although he may not have cared), and so he impregnated 49 or 50 of them. The women gave birth to 51 sons who are said to have colonized Sardinia.