The conservation group said it preferred the traditional terms after a twelve-foot-high banner at Avebury Manor displayed the BCE and CE annotations.
A spokesman told Premier: "The National Trust's editorial style is to use AD and BC when writing dates and this has been the case for many years.
"We do this to ensure a consistent approach and will be looking at the way the dates are written at Avebury Manor."
Visitors who complained about the banner told The Daily Telegraph they were informed by staff there have been numerous negative comments.
Hello, our editorial style is to use AD and BC when writing dates and this has been the case for many years. We do this to ensure a consistent approach across the places we care for. We'll be looking at the way dates are written at Avebury Manor.— National Trust (@nationaltrust) November 13, 2018
One tourist at the attraction, David Pearson told newspaper: "BC and AD go back an awful long way and they work perfectly well. If it isn't broken, why tamper with it?
"All it does is offend Christians, yet I very much doubt people of a different persuasion, or no persuasion, are offended by the normal version."
Last year, the National Trust was accused of "airbrushing faith" when the word Easter disappeared from marketing material promoting its annual egg hunt.
The use of BCE and CE have both grown during recent years. On the Religion and Ethics -Tool page of its website, the BBC says it favours the terms as a "religiously neutral alternative to BC/AD".
Anno domini means 'in the year of the Lord'.
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