Law / Am I eligible to apply for citizenship of Poland? [11]

So what about this scenario...my great-grandfather was born in what is now Poland, but was Russia at the time of his birth since it was prior to 1918 and Poland did not exist as a country. He emigrated to the United States in 1905. To my knowledge, nobody in my family has attempted to claim Polish citizenship based on my great-grandfather's nationality. Are we eligible?

Law / Am I eligible to apply for citizenship of Poland? [11]

That's what I thought; no huge disappointment, more mere curiosity.