They were there until the May breakout. Just about every square yard of the lodgement could be hit by German artillery. The Germans made a couple of attempts to crush the lodgement. Note that British and some Canadian troops were in the lodgement as well.

Anzio Annie...German railroad gun...
Prime Minister Churchill thought that Anzio landing was a good idea...I think that he was a great leader...But, Anzio landing was a mistake...