This thread from 4 years ago has the answers you need my friend. /u/Celebreth goes in depth. https://www.reddit.com/r/AskHistorians/comments/1riwc2/how_did_the_wives_of_roman_soldiers_learn_of/%3Futm_medium%3Dorganic%26utm_source%3Dgoogle_rich_qa%26utm_campaign%3Dgoogle_rich_qa