Complex sentence: In 1890, Rhodes sent a group of settlers, known as the Pioneer Column, into Mashonaland and when they reached Harari Hill, they founded Fort Salisbury (now Harare).
Split into simpler sentences: In 1890, Rhodes sent a group of settlers, known as the Pioneer Column, into Mashonaland. When they reached Harari Hill, they founded Fort Salisbury (now Harare).