How can I get the Middle English and Modern English from this page?

[ibreeden]

That is, all the content of p html tags is missing!

No, look carefully, not all of them are empty. I don't know what the empty P tags are for, but this one contains data you need. I am showing a fragment.

Output:
<p><span style="font-family:'book antiqua', palatino">859        <strong>Whilom, as olde stories tellen us,</strong></span><br /><span style="font-family:'book antiqua', palatino">                Once, as old histories tell us,</span><br /><span style="font-family:'book antiqua', palatino"> 860        <strong>Ther was a duc that highte Theseus;</strong></span><br /><span style="font-family:'book antiqua', palatino">                There was a duke who was called Theseus;</span><br />
...
<span style="font-family:'book antiqua', palatino"> 1000        <strong>But shortly for to telle is myn entente.</strong></span><br /><span style="font-family:'book antiqua', palatino">                  But briefly to tell is my intent.</span></p>

You need to look inside the P tags for SPAN tags with attribute style="font-family:'book antiqua', palatino". Then the "olde storie" will be in STRONG tags. I believe you wanted to skip this.