Adding old articles to blog

I would like to be able to add some old articles from a website to an archive page within the current blog, ideally in a way that makes/keeps them searchable.

The “Archives” on the blog are only month-by-month archives of entries posted since the blog began; these would be articles published prior to the blog that formerly sat in a static page on a website.

I am kind of at a loss for any way to do this, let alone the best way.

Any suggestions?