Helen of Bosnia

Whether she was a regent who ruled during an interregnum or a queen regnant is disputed, but in any case the real power was held by magnates of the kingdom.

[2] Queen Helen's family gained significant influence in state affairs during her husband's reign, as well as the right to collect the tribute of Ston from the Republic of Ragusa in 1393.

[2] Sigismund raised an army and marched to nearby Syrmia with the aim to claim the Bosnian throne, but the noblemen convoked a stanak and elected Helen as Dabiša's successor.

Not willing to engage the united nobility in war, Sigismund withdrew; the death of his wife Mary, heir of Hungary and cousin of Dabiša, made his position too precarious to attack Bosnia, as did the defeat by the Ottomans at the Battle of Nikopolis.

Ragusa eventually accepted that Helen would not confirm the charters granted by Bosnian monarchs to the Republic, apparently because she was not entitled to do so.

Having become virtually autonomous, her vassals engaged in internal warfare which weakened the Kingdom and precluded its participation in regional politics.

The Ottoman army that arrived in Bosnia in January 1398, led by Bayazid's sons and the subjugated Serbian lord Stefan Lazarević, was larger than those defeated by Helen's predecessors in 1388 and 1392.

[8] It seems that Helen's family, the Nikolić, attempted to take further advantage of their royal relations and free themselves from subordinacy to the House of Kosača and become immediate vassals of the monarch instead.