The "Crimson Ark" refers to the Cause of Baha'u'llah. His followers are
designated as the "companions of the Crimson Ark", lauded by the Bab in
the Qayyumu'l-Asma.
116. O Emperor of Austria! He Who is the Dayspring of God's Light dwelt in
the prison of Akka at the time when thou didst set forth to visit the Aqsa
Mosque. #85
Francis Joseph (Franz Josef, 1830-1916), Emperor of Austria and King of
Hungary, made a pilgrimage to Jerusalem in 1869. While in the Holy Land he
failed to take the opportunity to inquire about Baha'u'llah Who at that
time was a prisoner in Akka (Acre).
The Aqsa Mosque, literally, the "Most Distant" Mosque, is referred to in
the Qur'an, and has become identified with the Temple Mount in Jerusalem.