中世纪时，热那亚共和国和比萨共和国都非常强大。
The Republics of Genoa and Pisa were very powerful in the middle ages .
在中古时代，比萨是个共和国，有自己的政府，有自己的陆海军，还有很发达的商业。
Pisa was a republic in the middle ages , with a government of her own , armies and navies of her own , and a great commerce .
比萨共和国