1. Wales was linked to it in the thirteenth century.

2. Next England and Wales were joined to Scotland in the seventeenth century and the name was changed to "Great Britain".

在被动语态中，过去分词所表示动作的“施事者” 经常被省略。如果补上，需要有by 引出。怎么会是介词to 的宾语呢？介词to 后面的宾语表示“被连接的事物之一”。网友请看句子是如何转换的：

British people linked Wales to it (it = England). 

被动式：Wales was linked to it by British people.

Next British people joined England and Wales to Scotland.

被动式： Next England and Wales were joined to Scotland by British people.