Sis·tine 
(s
ĭs
t
ēn
′, s
ĭ-st
ēn
) also
Six·tine (s
ĭk
st
ēn
′, -st
īn
′)
adj.1. Of or relating to any of the five popes named Sixtus, especially Sixtus IV (1414-1484; reigned 1471-1484) and Sixtus V (1520-1590; reigned 1585-1590).
2. Of or relating to the Sistine Chapel in the Vatican, constructed by Sixtus IV on the site of an earlier chapel.
[Italian sistino, from New Latin sixtīnus, from Medieval Latin Sixtus, the name of several popes, from Latin Sextus, Roman praenomen, from sextus, sixth; see SEXT1.]