what are the titles of the different dukedoms in portugal?
duke of abrantes, duke of albuquerque, duke of aveiro, duke of avila and bolama, duke of barcelos, duke of beja, duke of braganza, duke of cadaval, duke of caminha, duke of coimbra, duke of faial, duke of ficalho, duke of goa, duke of guarda, duke of guimaraes, duke of lafoes, duke of linhares, duke of loule, duke of miranda do corvo, duke of palmela, duke of porto, duke of saldanha, duke of tancos, duke of terceira, duke of torres novas, duke of trancoso, duke of vila real, duke of viseu, duke of vitoria
of these, which share the same creation date?
duke of coimbra, duke of viseu
which of these had henry, the navigator, prince of portugal as it's first titular?
duke of viseu