Together, we are the United Nations
Gunulfr ok Øgotr ok Aslakr ok Rolfr resþu sten þænsi æftir Ful, felaga sin, ær warþ ... døþr, þa kunungar barþusk.
Vienna is under ottoman banner.
4 regulars are in.
Suleiman and 4 cavalry are in Pressburg.
Charles, Alba, Ferdinand and 15 regulars are in Graz.
The entire haps stack moves into Vienna.
A battle is genered.
Haps play landsknechts.
Ottos play Field Artillery.
Roll dice and the result is 8-8.
The defender wins in that situation?
Yes, the defender always wins ties. See step 8 of the Field Battle Procedure (paragraph 14 of the rules).
Suleiman is captured? Where he goes?
Suleiman goes to the Habsburg power card as specified in step 10 of the Field Battle Procedure.
Has the haps army to retreat to Graz?
Yes, a losing attacker always retreats to the space he came from (14.1).
If haps have to retreat, can they move any more this impulse?
No, see 13.1 - "No army leader or unit may participate in a Move action if it was part of a formation that lost a field battle earlier in the impulse."