Original: Straight rail , sometimes referred to as carom billiards , straight billiards , the three-ball game , the carambole game , and the free game in Europe , is thought to date to the 18th century , although no exact time of origin is known .
Simplified: Straight rail , sometimes called carom billiards , straight billiards , the three-ball game , the carambole game , and the free game in Europe , is thought to date to the 1700s . No exact time of origin is known though .