Martinuzzi took two drastic steps in response: he arrested the queen and appealed to the Ottoman Empire for help.
John Zápolya had requested Ottoman aid against Ferdinand; in return, Hungary was an Ottoman vassal state, and Martinuzzi asked Ottoman Sultan Suleiman to defend his vassal against attack.
An Ottoman army repulsed the Austrians.

On 28 August 1541 Martinuzzi, the queen, and the infant king went to the Ottoman camp, where he paid homage to the sultan as regent.
During their absence, the Ottoman Grand Vizier seized Buda by subterfuge, causing Martinuzzi to realize the need for accords with Austria and the Ottoman Empire.
This led to the 29 December 1541 Treaty of Gyalu, in which Ferdinand received western Hungary; the Eastern Hungarian Kingdom (an independent principality under Ottoman suzerainty) was reverted to John Sigismund.
This region included many Hungarian counties on both sides of the Tisza and the city of Kassa (now Košice).
Martinuzzi's policy was to keep the state neutral (and intact) by cultivating amicable relations with Austria without offending the Ottomans.
Although this was difficult, it succeeded for a time.

Encouraged by Ferdinand's growing unpopularity (due to his inability to defend Hungary against the Turks), in 1545 Martinuzzi, to ensure John Sigismund's election as king, wanted to unite Habsburg Kingdom of Hungary and Eastern Hungarian Kingdom.
Realizing that this was impossible, he aimed at an alliance with Ferdinand on terms of relative equality (a policy he followed until his death).

In 1550 Queen Isabella (who opposed Martinuzzi) complained about him to the Sultan, who ordered that Martinuzzi or his head be sent to Constantinople.
A coalition formed against Martinuzzi composed of the queen, the hospodars of Moldavia and Wallachia, and the Turks.
The regent imprisoned the queen in Gyulafehérvár (now Alba Iulia), drove the hospodars out of Transylvania, and defeated the Turks at Déva (now Deva).
He compelled Isabella to accept terms with Ferdinand advantageous to her family and Transylvania, and placated the sultan with flattery and gifts.
This agreement was confirmed by the diet of Kolozsvár (now Cluj-Napoca) in August 1551; Martinuzzi remained governor of Transylvania, and was ordained Archbishop of Esztergom.
On 12 October 1551 Pope Julius III named him a cardinal, with permission to wear the habit of his order instead of a cardinal's robes.

Although Hungary was again reunited, Ferdinand's inability to defend it against the Ottomans forced Martinuzzi to resume the payment of tribute to the sultan in December 1551.
However, the Ottomans no longer trusted a diplomat whose behavior they could not understand, and Ferdinand suspected him of wanting to secure Hungary for himself.
Martinuzzi took two drastic steps in response: he arrested the queen and appealed to the Ottoman Empire for help. John Zápolya had requested Ottoman aid against Ferdinand; in return, Hungary was an Ottoman vassal state, and Martinuzzi asked Ottoman Sultan Suleiman to defend his vassal against attack. An Ottoman army repulsed the Austrians.
On 28 August 1541 Martinuzzi, the queen, and the infant king went to the Ottoman camp, where he paid homage to the sultan as regent. During their absence, the Ottoman Grand Vizier seized Buda by subterfuge, causing Martinuzzi to realize the need for accords with Austria and the Ottoman Empire. This led to the 29 December 1541 Treaty of Gyalu, in which Ferdinand received western Hungary; the Eastern Hungarian Kingdom (an independent principality under Ottoman suzerainty) was reverted to John Sigismund. This region included many Hungarian counties on both sides of the Tisza and the city of Kassa (now Košice). Martinuzzi's policy was to keep the state neutral (and intact) by cultivating amicable relations with Austria without offending the Ottomans. Although this was difficult, it succeeded for a time.
Encouraged by Ferdinand's growing unpopularity (due to his inability to defend Hungary against the Turks), in 1545 Martinuzzi, to ensure John Sigismund's election as king, wanted to unite Habsburg Kingdom of Hungary and Eastern Hungarian Kingdom. Realizing that this was impossible, he aimed at an alliance with Ferdinand on terms of relative equality (a policy he followed until his death).
In 1550 Queen Isabella (who opposed Martinuzzi) complained about him to the Sultan, who ordered that Martinuzzi or his head be sent to Constantinople. A coalition formed against Martinuzzi composed of the queen, the hospodars of Moldavia and Wallachia, and the Turks. The regent imprisoned the queen in Gyulafehérvár (now Alba Iulia), drove the hospodars out of Transylvania, and defeated the Turks at Déva (now Deva). He compelled Isabella to accept terms with Ferdinand advantageous to her family and Transylvania, and placated the sultan with flattery and gifts. This agreement was confirmed by the diet of Kolozsvár (now Cluj-Napoca) in August 1551; Martinuzzi remained governor of Transylvania, and was ordained Archbishop of Esztergom. On 12 October 1551 Pope Julius III named him a cardinal, with permission to wear the habit of his order instead of a cardinal's robes.
Although Hungary was again reunited, Ferdinand's inability to defend it against the Ottomans forced Martinuzzi to resume the payment of tribute to the sultan in December 1551. However, the Ottomans no longer trusted a diplomat whose behavior they could not understand, and Ferdinand suspected him of wanting to secure Hungary for himself.
George Martinuzzi