John Gill Commentary Mark 12:22

"and the seven left no seed. Last of all the woman also died." — Mark 12:22 (ASV)

And the seventh had her, and left no seed
All, the seven brethren married her, one after another, and neither of them had any children by her:

and last of all the woman died also ;
after all the seven brethren, to whom she had been married.