Answer by taking a quote from the following article:

Cronje was born in Bloemfontein, South Africa to Ewie Cronje and San-Marie Cronje on 25 September 1969. He graduated in 1987 from Grey College in Bloemfontein, where he was the head boy. An excellent all round sportsman, he represented the then Orange Free State Province in cricket and rugby at schools level. He was the captain of his school's cricket and rugby teams.

Cronje's form in 1991/92 was impressive especially in the one-day format where he averaged 61.40. He earned an international call up for the 1992 World Cup, making his One Day International debut against Australia at Sydney. During the tournament he played in eight of the team's nine games, averaging 34.00 with the bat, while his medium pace was used in bowling 20 overs. After the World Cup Cronje was part of the tour to the West Indies; he featured in the three ODI's, and in the Test match at Bridgetown that followed, he made his Test debut. This was South Africa's first Test since readmission and they came close to beating a strong West Indian side, going into the final day at 122/2 chasing 200 they collapsed to 148. India toured South Africa in 1992/93. In the first one-day international, he hit the famous six when his team needed 6 runs off only 4 balls, and was awarded Man of the match for his bowling. In the one-day series, Cronje managed just one fifty but with the ball he was economical and took his career best figures of 5/32, becoming the second South African to take five wickets in an ODI. In the Test series that followed he scored his maiden test century, 135 off 411 balls, after coming in at 0-1 in the second over he was last man out, after eight and three-quarter hours, in a total of 275. This contributed to South Africa's first Test win since readmission. At the end of the season in a triangular tournament with Pakistan and West Indies he scored 81 off 70 balls against Pakistan. In South Africa's next Test series against Sri Lanka, Cronje scored his second Test century, 122 in the second Test in Colombo; the victory margin of an innings and 208 runs is a South African record. He finished the series with 237 runs at 59.25 after scoring 73* in the drawn third Test.

What is his maiden test century?
135 off 411 balls, after coming in at 0-1 in the second over he was last man out, after eight and three-quarter hours, in a total of 275.