Casio was established in 1946 and ventured into wristwatches in the 1980s. They were one of the earliest manufacturers of quartz watches, both digital and analog. 
They continued to innovate and created watches that could display time in multiple time zones, watches with altitude, barometer and compass (ABC) functions, temperature measurements, and even global positioning systems (GPS). 
Their G-Shock and Baby-G lines are very popular even till this day.