 The imperial army invaded the Papal States under the command of Rainald of Urslingen in October 1228 . Although John defeated the invaders in a series of battles , it took a counter @-@ invasion by another papal army in southern Italy to drive Rainald back to Sulmona . John laid a siege before returning to Perugia in early 1229 to conclude negotiations with envoys of the Latin Empire of Constantinople , who were offering him the imperial crown . 
 The imperial army invaded the Papal States under the command of Rainald of Urslingen in October 1228 . Although John defeated the invaders in a series of battles , it took a counter @-@ invasion by another papal army in southern Italy to drive Rainald back to Sulmona . John laid a siege before returning to Perugia in early 1229 to conclude negotiations with envoys of the Latin Empire of Constantinople , <a href='null_relcl' title='1'><mark>who</mark></a><a href='uninflect' title='2'><mark>were</mark></a> offering him the imperial crown . 
The imperial army invaded the Papal States under the command of Rainald of Urslingen in October 1228 . Although John defeated the invaders in a series of battles , it took a counter @-@ invasion by anotha papal army in southern Italy to drive Rainald bacc to Sulmona . John laid a siege before returning to Perugia in early 1229 to conclude negotiations with envoys of the Latin Empire of Constantinople , was offering em the imperial crown .