Much have I travelled in the realms of gold
And many goodly states and kingdoms seen;
Round many western islands have I been
Which bards in fealty to Apollo hold.
Oft of one wide expanse had I been told
That deep-browed Homer ruled as his demesne;
Yet did I never breathe its pure serene
Keats' alienation is explained further here through the image of  Apollo , the mythical Greek god, who nudges the poet and therefore the reader closer geographically to Homer' 
 “Fealty” is a pledge of allegiance, usually religious. The dedication to Apollo is apt, as he is the god of poetry and music amongst other attributes. 
 
 The “bards”, historically meaning performance poets,   symbolise those who are religiously committed to literature. Keats implies that he wants to join them, but at this stage is too diffident.