Help with a view

I've created a view 'principals' that gives me this output:

pgslekt=> select * from principals where event=15821;
person | event | place | sort_date | tag_type
--------+-------+-------+------------+----------
2 | 15821 | 1152 | 1999-09-17 | 4
3 | 15821 | 1152 | 1999-09-17 | 4
(2 rows)

How do I go about selecting the "other" person of this event, given that
I have one of them and the event number?

I'd also like a view that gives me the two rows combined into one, with
"person" replaced by p1 and p2.
--
Leif Biberg Kristensen
http://solumslekt.org/