 During the Battle of the Bridge against the Sassanids in 634, another of Zayd's sons, Urwah, participated and was said by al-Baladhuri to have "fought so fiercely that his action was estimated to be equivalent to be that of a whole group of men".During the battle, Christian Tayy tribesmen on the Sassanid side defected to the Muslim army, preventing an imminent Muslim rout.Among those who defected were the poet Abu Zubayd at-Ta'i.