Same size as the Gotha but only 2/3 the range so it couldn't bomb London. But the Gotha is the famous one even though less than 50 were built while the G.III was a better plane with almost 1000 built and it was well used on the western front for night bombing.
The Germans also had a 4 engine bomber called the Giant - I think the wingspan was 132 ft vs. 78 ft for the Gotha and G.III. The Giant made a few raids on London. I think less than 20 were built.
Terry