Should it be 'were' instead of 'was'?

During the same period of time, in the USA, the area of New York was given its present name. In China, that was the time the Qing dynasty and Isaac Newton found the law of universal gravitation in England. The Palace and Park of Versailles was established in France. It was also the time of the Johor Empire around the Strait of Malacca.

Not only the situation of each country but also the way of thinking in the world during the time of Nichikan Shonin were different from now. Especially in Japan, it was the time of national isolation when Japan closed its doors to the rest of world other than China and the Netherlands for about 200 years.

1. Should it be 'were' instead of 'was'?
2. Should it be 'are' instead of 'were'?

Thanks.