I think Perl5 was originally planned to be replaced by Perl6. Then Perl6 took much longer than anyone expected, and kinda ended up in a different place. Perl5 was re-anointed as the once-and-future Perl, and what had been Perl6 became Raku.
If I remember correctly, somewhere in the middle of all that there was talk of running Python (and other languages) on the new Perl6 VM.