Quote Originally Posted by King Edward
Byz Infantry are a great early unit but soon get outcalssed in the High and Late periods by the heavy catholic units or turkish janissary units. Also no decent spears makes the Byz vulnerable to cavalry.

As far as i know Hold position gives +2 Def and -2 Attack. (As already stated.)
sorry, as Maeda Toshiie pointed out, that's hold formation.
Hold position, again, as already stated, has no effect in combat (other than it just tells the unit to stay there). No bonuses, no antyhing.