What Stood On The Site Of St. Paul's Cathedral (London) Before The Present Building?

It seems like this has been a site of worship since time immemorial.  Under the early Roman invaders, this was a site of worship dedicated to the moon and the hunting Goddess Diana.  Some historicans reckon that the Romans actually used an existing stone circle for their temple, in an effort to convert the locals to their own creed, which would make it a religious site for much longer before the Romans came.  This may have then become a Christian site of worship in the the 4th century AD, when Christianity was declared the Roman Empire state religion.  

The first documented church building (Saxon) was created in 604 AD, only 8 years after the missionary St. Augustine arrived in Kent.

That burnt down in 675 AD, and was rebuilt by Bishop Erkenwald.  His tomb became a place of pilgramage in the middle ages.  

Erkenwald's building was burned repeatedly, especially in 962 (when London was raided by Vikings) and again in 1087, shortly after the Norman conquest.  The next Cathedral was started after 1087, although it took more than 150 years to complete.  That burnt down in 1666, and the modern (current) cathedral was rebuilt and finished by 1710.