Protestants must help uncover the truth of past atrocities in Northern Ireland, the head of the Orange Order has said.
Orangemen across Northern Ireland have been holding their annual Twelfth of July celebrations. Up to half a million people were involved in 18 demonstrations.
Grand Master of the Grand Lodge of Ireland Edward Stevenson addressed a gathering in Limavady, Co Londonderry.
"The recent (Kingsmills) report by the Historical Enquiries Team (HET) pointed the finger very clearly at the sectarian murderers of the IRA and I have no doubt there will be many other similar verdicts," he said.
"Protestants and Orangemen must engage with the HET so that the wider public can hear the truth about what really happened in this society over three decades."
A group of 10 Protestant workmen were shot dead by the IRA in 1976 in Kingsmills, Co Armagh. The sole Catholic in the vehicle was allowed to walk away.
The HET, a unit of detectives which is reinvestigating unresolved killings in Northern Ireland, published the findings of its probe into the massacre last month.
It found that the IRA was responsible and that victims were targeted because of their religion.
The HET said that the rifles fired at Kingsmills had been used in as many as 90 other murders and attempted murders.
The families of the murdered men have called for a public inquiry. The Grand Master said around 330 Orangemen lost their lives to terrorism during the Troubles.