Not much can be said about the orbit of 39P/Oterma before the 19th century. It could have been anywhere either inside the orbit of Jupiter (least probable), between the orbits of Jupiter and Saturn (most probable), or even a Saturn-crossing one. Anyhow, even if it had not been there before, with a probability of 20% a close encounter (< 2 AU) with Jupiter happened between 1815 and 1817 which brought the orbit of 39P/Oterma for a longer period in a defined orbit. Thus at least from the beginning of the 19th century till 1937 the comet's orbit was framed by Saturn's orbit on the outside and Jupiter's orbit in the inside. That means, 39P/Oterma was at this period a centaur-like object as it is today with no chance of being observed from Earth.