Hello Mr. Sorenson.
"Xbre" is common shorthand in French and Italian for décembre/dicembre, i.e. the month of December. It's was originally the tenth month, hence the roman numeral "X" in it (but you probably already knew that). The Roman numeral XIV means 14 of course, but "December 15, 1914" is slightly unlikely.
I've never seen Vittorio Jano's (János Viktor's) signature anywhere, so I can't comment on it.
"Xbre" is common shorthand in French and Italian for décembre/dicembre, i.e. the month of December. It's was originally the tenth month, hence the roman numeral "X" in it (but you probably already knew that). The Roman numeral XIV means 14 of course, but "December 15, 1914" is slightly unlikely.
I've never seen Vittorio Jano's (János Viktor's) signature anywhere, so I can't comment on it.