Depends on the Ancients ~ the Hindus may have had a concept of a very large universe, but the fellows in the West and Middle East didn’t ~ maybe a galaxy or two, but nothing like 26 billion lightyears wide. They even thought of the stars as holes in the sky ~ maybe revealing Heaven beyond, but nothing more than that.
Here's the passage Lewis quoted, from Ptolemy's Almagest; he quotes Book 1, Chapter 5 as follows;
"the Earth, in relation to the distance of the fixed stars, has no appreciable size and must be treated as a mathematical point".
Cheers!