From the records of the Constitutional Commission, to the amicus curiae briefs of two former Constitutional Commissioners, it is without a doubt that the term "to initiate" refers to the filing of the impeachment complaint coupled with Congress' taking initial action of said complaint.
Having concluded that the initiation takes place by the act of filing and referral or endorsement of the impeachment complaint to the House Committee on Justice or, by the filing by at least one-third of the members of the House of Representatives with the Secretary General of the House, the meaning of Section 3 (5) of Article XI becomes clear. Once an impeachment complaint has been initiated, another impeachment complaint may not be filed against the same official within a one year period.
Under Sections 16 and 17 of Rule V of the House Impeachment Rules, impeachment proceedings are deemed initiated (1) if there is a finding by the House Committee on Justice that the verified complaint and/or resolution is sufficient in substance, or (2) once the House itself affirms or overturns the finding of the Committee on Justice that the verified complaint and/or resolution is not sufficient in substance or (3) by the filing or endorsement before the Secretary-General of the House of Representatives of a verified complaint or a resolution of impeachment by at least 1/3 of the members of the House. These rules clearly contravene Section 3 (5) of Article XI since the rules give the term "initiate" a meaning different meaning from filing and referral.