the unk crusades ( unk ) were two crusades Military_operation sent by pope clement vi against the emirate of aydin under umur beg which had as their principal target the coastal city of smyrna in asia minor .

the power struggle ignited Process_start around social and financial troubles following the hundred years ' war , unfolding the structural problems of bastard feudalism , combined with the mental infirmity and weak rule of king henry vi which revived interest in the house of york 's claim to the throne by richard of york .