Large German Shell from WWI

[JohnB]

Gentlemen,
Could anyone tell me exactly what type of German Gun fired projectiles from this shell? I have seen these around quite a bit and every one I have seen has the same dimensions -- about 8 1/4 inches in diameter and 9 inches tall. So they are not cut down. Every one I have seen is also dated from WWI. I would like to know what their role was in the war.
Kind regards,
John

[JohnB]

Here is a picture of the bottom of the shell.
Thank you,
John

[AndyD]

If I remember correctly,that's a shellcase from the 21cm morser (howitzer).

Should be an umlaut over the o but can't do them on this keyboard!

Kind regards,
Andy

[JohnB]

Thank you Andy!