Do not be ridiculous. Nobody knows what had been happening in Silesia in IV century because all people who may be living there -- German or Polish - were illiterate pagans. However, it is well-known what happened afterwards, in particular, that Silesia was part of the Holy Roman Empire, which was de-facto German state. I do not have time to lecture you on history of your own country, but you could read it all
here. Your trick about 1871 is a quite silly one. There was no German empire until 1871, yes, but this does not mean that there were no German states before that. Silesia was inhabited by Germans who spoke German and lived by German laws for a long time since at least 13th century.
Since when truth is ridiculous? jb6 stated Silesia was German since 1600 years ago, which was a childish silliness. And you are making a fool of yourself defending ignorance. Please lecture me on the history of my country. I am always eager to get to know something new from such a honorable his-storian.