Ney’s Corps had started to besiege Ciudad Rodrigo on 26 April so Gallegos was very much in the front line. The Light Division had no need for a number of Catholic Priests unless this was some form of ‘Human Shield’ to deter a French attack.
Or, 4 May was St Pelagia of Tarsus day. Perhaps they were the ‘Priests of Tarsus’ and had crossed over the border and got a bit carried away with their celebrations the day before !!!
Paul