Peter Cain, the ACT’s shadow attorney general, has apologised “wholeheartedly” for a 2002 workbook he wrote which does not mention the frontier wars and paints a rosy picture of how Christian settlers helped First Nations peoples.

In History of Australia, a student workbook and teacher’s manual published by Light Educational Ministries, Cain wrote that when the British arrived, “some were afraid of the Aboriginals; some treated them badly”.

“But the governors tried to protect the Aborigines and encouraged Christians to tell them about the Gospel of the Lord Jesus Christ. The Christians also tried to help the Aboriginals by caring for them and teaching them English so they could be part of the growing settlement,” he wrote.

One exercise talks about the “unfortunate things that happened” with colonisation then asks students to discuss how Aboriginal people have been “blessed” by the British coming.

In another section Cain talks about the conversion of First Nations people.

“Darwinian evolution actually taught that some Aboriginal people on the Earth represented a lower stage of humanity in the evolutionary tree,” he wrote.

“The Origin of the Species [sic] influenced some during the nineteenth century to see Aboriginal peoples as inferior and not worth the full rights of other human beings.

“In a Christian perspective all human beings are made in God’s image and one of the responsibilities for the Christian Church is to make disciples of the nations … generally speaking, the settlement of Australia was accompanied by a desire to help Aboriginal peoples.

“The gospel of Jesus Christ is no doubt greatly appreciated by the many Aboriginal Christians in this land today. Even those Aboriginals and non-Aboriginals who do not consider themselves Christian receive the benefits of a society that still operates in many spheres upon Christian presuppositions and order.”

Cain also described God as the “creator of Australia” and said he made plans for the various tribes and nations “in the hope that they might find the truth about God”.

“God knew the Aboriginal peoples and made a plan for their salvation,” he wrote.

Asked about the books, Cain told Guardian Australia he had “sincere respect for the Aboriginal and Torres Strait Islander community”.

“And I wholeheartedly apologise for any offence given,” he said.

“My own understanding of First Nations history and culture has developed considerably in the over two decades since the student workbook was authored and published.”

Prof Bronwyn Carlson, from Macquarie University’s Critical Indigenous Studies department, said she was glad Cain had apologised and had learned more about Indigenous cultures.

“Hard to imagine that such nonsense was written only two decades ago,” she said.

“I am glad Mr Cain has apologised for such ridiculous statements – it is a demonstration of how power works that this nonsense was even in circulation.

“I am sure he is very embarrassed – I would be.”

The workbook and manual were published by Light Educational Ministries, which sells books for home schoolers and Christian schools. Its bookstore still sells a similar workbook and manual but does not appear to stock Cain’s.

Cain’s personal website states he had a 20-year career as a high school mathematics teacher and worked as principal in the non-government school sector before his election to the ACT Legislative Assembly in October 2020.

Cain is the Canberra Liberal’s member for Ginninderra.

Canberrans head to the polls for the ACT election on 19 October.

Another Ginninderra Canberra Liberal Elizabeth Kikkert was dumped by the party two weeks ago and is now running for Family First.

Darren Roberts will also run as a Liberal candidate for Ginninderra, despite a recent controversy over social media posts.

Labor’s Andrew Barr is the longest-serving chief minister of the ACT.