The Alliance Party was formed in April 1970. Many of its key leadership figures, along with early membership, came from the New Ulster Movement, a pressure group established in 1969 and broadly supportive of the modernising tendencies of UUP leader Terence O'Neill.
Alliance, at that point, was clearly and deliberately a pro-Union party; albeit a party which was uncomfortable with what it regarded as the "sectarian manifestation" of Ulster unionism.
And standing under that liberal unionist banner, Alliance, in the eight elections it contested in its first decade, averaged a very respectable 10% - reaching almost 15% in 1977.
In an interview in yesterday's Belfast Telegraph, Naomi Long, who will be confirmed as leader in two weeks, said that Alliance "don't define ourselves as a unionist party".
Does that matter? I think it does if the party hopes to get back to breaching that 10% figure (something it hasn't done for a very long time) and moving itself from fifth-party status to fourth or even third.
Naomi has said before that Alliance is "not divided along a binary cleavage of unionist or nationalist", which is similar to David Ford's nuanced agnosticism of Alliance being a party for "unionist, nationalist and people disinterested in the border".
Her problem in terms of growing Alliance's support, which is averaging between 6-7% at the moment, is that agnosticism doesn't usually convert into solid votes.
She did well in East Belfast in 2015/16 (she won the seat in 2010 on the back of unionist disunity and growing dislike of Peter Robinson) because many unionists, particularly in the UUP, don't need their beliefs wrapped in a Union flag and admired the personal courage she displayed during the flag protest period.
They were prepared to use their vote as their own personal protest, but it didn't mean their unionism or belief in the UK had been diminished or diluted. And it certainly didn't mean they had any time for Anna Lo's view that a "unified Ireland would be better placed economically, socially and politically".
She also needs to bear in mind what happened to NI21 in their first elections in June 2014, when they tanked with 1.7%. Fair enough, they weren't helped by the personal stuff which broke on the eve of the election, but I think far more damage was done by the announcement that they wouldn't designate themselves as 'unionist' in a future Assembly - something that came as a huge shock to some members, candidates and potential voters, who were under the impression that the party was small 'u' and pro-Union.
It will be interesting to see if Mike Nesbitt and Arlene Foster try to exploit Long's comments and seek to portray her as anti-unionist. The UUP is running behind Alliance in Belfast in terms of votes, councillors and MLAs and will be keen to gain ground.
Also, neither the DUP, UUP, nor the smaller unionist parties will want the impression strengthened that they require an election pact to fend off the Alliance challenge in any Belfast constituency - particularly with the proposed boundary changes.
Naomi Long needs to tread carefully. Alliance tends to do better in unionist constituencies east of the Bann because enough liberal, small 'u' unionists still regard them as a broadly pro-Union party.
So unionist parties will almost certainly - and knowing that she was brought up in a working-class loyalist background - challenge her unionist credentials as never before.
She is going to be asked tough questions. She'll need coherent, vote-attracting answers if that 10% threshold is to be crossed.