Ruth 1:5

‘ And Mahlon and Chilion died both of them, and the woman was left by her two children and by her husband.'

The two sons also died. This may have been as a result of some pestilence or illness, the effect of which was possibly exacerbated by their weakly condition, or it may have been at the hands of brigands. That they apparently died around the same time would suggest some such thing. But it resulted in the consequence that Naomi found herself alone in a foreign country, with no sons and no husband, something which she had not foreseen.