Sorry for what is essentially a newbie connection:
If i have a branch, that i essentially am using as parent, i create a few children branches from it, and then rename (i.e. copy and delete) the parent, won't the children branches be fatherless and hence lose considerable amount of their history?
No. Deletions in subversion do not actually destroy any data.
For example, if you delete http://svn.example.com/myproject/somebranch in revision 5, then the deleted branch is still accessible as http://svn.example.com/myproject/somebranch@4. That "@4" is called the peg revision. Also, if you examine the history of "child branches" then the history of the deleted "parent branch" will still be visible.
Unlike the command line client, TortoiseSVN does not support the @ peg revision syntax for URLs. Instead, you can click the "HEAD" revision button in the upper right corner of the repo-browser and enter a different revision.
In a browser, you can append ?p= to the URL instead of @ like this.