After having declined in size following the subjugation of the Mediterranean, the Roman navy underwent short-term upgrading and revitalisation in the late Republic to meet several new demands. Under Caesar, an invasion fleet was assembled in the English Channel to allow the invasion of Britannia; under Pompey, a large fleet was raised in the Mediterranean Sea to clear the sea of Cilician pirates. During the civil war that followed, <answer>as many as a thousand ships</answer> were either constructed or pressed into service from Greek cities.
Around how many ships were sent into service from Greek cities?
as many as a thousand ships