 यस्येयं प्रथमं दत्ता समृद्धा मनुना मही।तमिक्ष्वाकुमयोध्यायां राजानं विद्धि पूर्वकम्।। 
 Manu had orginally bestowed the most prosperous earth on Ikshvaku and you know  Ikshvaku was the first king of Ayodhya. 