January 6

It seems likely that Bahá'u'lláh's Tablet to the Pope [Pius IX] was never delivered to him. We do not know the method used to transmit it to him, and can only guess that Church dignitaries would not have attached sufficient importance to it to deliver It. ...it would be wonderful if it were actually found in the Vatican archives. The original was written in Arabic. In 1868 Bahá'u'lláh arrived in 'Akka, and the Tablet was supposedly sent from there about that period. Unfortunately this is the closest we can come at present to an accurate date. 
- Shoghi Effendi  (From a letter dated 15 November 1947 written on behalf of Shoghi Effendi to an individual believer; Memorandum from the Research Department of the Universal House of Justice dated 20 November 1989)