The assembly members were invited to sign the register, in alphabetical order of their parties, designating themselves as unionist, nationalist or other.
It seemed a far cry from 2006 when civil partnerships were decisively rejected, and a sign of shifting attitudes among the elders and ministers who make up the Assembly.
The deputy first minister Ieuan Wyn Jones, for Plaid Cymru, said that the maturity of the debate - where 18 assembly members all spoke in favour of a referendum - was a sign of the evolution of the institution.
If there is no sign of decommissioning by the end of January, the party will be expected to resign as threatened from the Assembly's power-sharing executive.