“家系的”用英语怎么说？

我们家系的实际创始人是我祖父的哥哥.The actual founder of my line was my grandfather's brother.根据家系的原理,这个事实即时可以得到解释.This fact is at once explained on the principle of descent.从此以后,倭马亚家系的繁荣就衰落了.From this point onward the glory of the ...