Jiu-jitsu is a mixture of several martial arts, including parts of aikido and I think judo
It's the other way around!
Actually, "judo" is the modern/derived sport (late 1800's) largely (but not solely!) from jiu-jitsu by the founder Jigaro Kano.
Aikido is even more modern, created by "the founder" (O-Sensei Morihei Ueshiba) in the early/mid part of last century. It is based on earlier systems, including "aiki-jujutsu." Ueshiba was a very spiritual man, and his art reflects this; it's one of the least "combative" martial arts around.
Finally worth noting is the "Gracie" (also called "Brazilian") style of jiu-jitsu, which is a bit less formalized (and much more groundwork & grapple-centric) than most of the ancestral Japanese styles. A key figure was actually a Judoka who specialized in groundwork, who introduced the Gracie family to his style.
Jiu-jitsu itself (formalized styles of grapple-centric combat in Japan) is well over 1000 years old, with earliest written records about 1300 years ago, although the name "jujutsu" (or however you want to latinize the spelling) is "only" a few centuries old.
Here endeth the martial-arts geekery. ;-)