Guitars are very popular instruments and usually had 6 strings, but back then, they only had four strings, smaller body and a smaller neck.
Guitar History:
1200 BC - Romans developed the Cithara, a stringed instrument.40 AD - The Romans went to Spain and Portugal and brought the Cithara there.
700 AD - Moors conquer where the Cithara is popular and makes a new instrument called Oud. The Oud is a modification of the Cithara.
1400 - The Vihuela was made and was the preferred stringed instrument for the next 200 years.

1800 - General alterations were added to the baroque guitar. These included fan struts, a raised neck and a fretboard made out of ebony wood.
1890 - Antonio Torres Jurado upgrades the guitars by increasing the body size and the neck size. This is what our modern classic guitar looked like.
1900 - Present - Guitars are with steel strings with bigger size and louder volume and are called acoustic guitars. Then guitars are amplified, becoming electric guitars and are used in countless styles of music.
The bass guitar replaced the double bass massively. It is one of the most important instruments in music. The bass guitar is a separate instrument to the double/upright bass even though they are tuned the same way.
Bass History:
Late 1500- There was an instrument called Viola De Gamba. It was a small double bass with 6 strings and was tuned the same as a double bass. It was like a guitar and an upright bass combined.1910 - Mandobasses were very similar to bass guitars but they weren't really that popular. It was an acoustic instrument.
1933 - The double bass was used in rock, jazz and e.t.c. but it was to bulky and heavy to carry around so people wanted a smaller, sleeker version and thus the first true electric Bass Guitar was made by Paul Tutmarc.
1936 - Rickenbacker invented a bedpost-bass. It looked A LOT like an upright/double bass but was still amplified by electricity.
1947 - Everett Hull was another Bass Guitar designer. He was working on one and then eventually, he made a pickup for double/upright basses. It cost around $37.50.
1951 - Leo Fender invents a percussion Bass Guitar.
1957 - The pickup was changed to be a split pickup and the headstock and the pickguard were redesigned.
1960 - Fender makes a Jazz Bass which is different to a Bass Guitar because it had two separate pickups than a split pickup.
1961 - Present - A lot of stuff happened and then the Bass Guitar was used in a lot of music and is still very important in music.