The phrase "wert in force" is pronounced /wəːt ɪn fɔːs/ with the first word spelled w-e-r-t. "Wert" is an archaic form of "were" which was commonly used in Middle English texts. It is the second person singular past tense of the verb "be". In modern English, "were" is used for the second person singular and plural as well as the first and third person plural. "Wert in force" means you were in power or authority, and it is often used in legal language.