Through Junayd, the alliance was extended to include the neighbouring rulers of Sarukhan, Menteshe, Teke and Germiyan. It is unclear if by this time Junayd was a vassal of Süleyman as he became later. Kastritsis concludes that if he was, then Junayd's support of İsa was probably in alignment with Süleyman's policy of supporting İsa against Mehmed. The allies held superior numbers, but Mehmed was able to overcome them in a battle near Smyrna, assisted by his own alliance with the Karamanids and the Beylik of Dulkadir. To maintain his authority, Junayd was forced to submit to the victor and ask for pardon, while İsa, trying to escape, was caught and strangled at Eskişehir. Worried by Mehmed's increasing power, Süleyman invaded Anatolia himself in late 1403 or early 1404, and occupied Bursa. Unable to face his brother's superior forces, Mehmed withdrew east to Rûm, and the stand-off between the two brothers entered a period of relative stalemate that lasted until 1410. In spring 1405, Junayd assembled a force of "more than five hundred troops", including many Smyrnaeans, with which he captured Ayasoluk and evicted the Aydınid brothers, Isa and Umur from their principality. According to Doukas, Junayd claimed to be operating on behalf of Süleyman, who supported Junayd with money. In the struggle that followed, the Aydınids appear to have been backed by Mehmed. A report from the Venetian colony of Crete suggests that, in early summer 1405, Mehmed allied himself with the rulers of Aydın (Umur) and Menteshe, and that Junayd sided with Süleyman in opposing them. Isa of Aydın was killed by Junayd near Palaiopolis, but Umur escaped. Umar's uncle, Ilyas Bey, ruler of Menteshe, marched against Ayasoluk in support. Doukas puts the force at 6,000 men, against the 3,000 of Junayd and the Kara-subashi. The town was held by the Kara-subashi, while Junayd held Smyrna. Ayasoluk surrendered after a two-day bombardment with incendiary missiles, but the Kara-subashi held the citadel until his surrender in autumn.