A system configured to fold an envelope sheet around one or more insert sheets (322, 324) to create a mailpiece, the system comprising: an insert transport path configured to transport the one or more insert sheets (322, 324) to a merge region; a primary transport path configured to transport the envelope sheet to the merge region, wherein the insert transport path is parallel to and/or vertically above the primary transport path; an insert stager that is connected to the insert transport path and arranged proximate to the primary transport path at the merge region, wherein the insert stager is configured to receive the one or more insert sheets (322, 324) from the insert transport path in a form of an insert stack, hold the insert stack, and to dispense the insert stack onto the envelope sheet when the envelope sheet is at a first position on the primary transport path, wherein the insert stack is dispensed from the insert stager at substantially a same speed as a speed of the envelope sheet along the primary transport path; one or more adhesive applicators configured to apply an adhesive along lateral edges of a back side portion of the envelope sheet as the envelope sheet is fed into a buckle folder; a buckle folder system configured to form an unsealed envelope for the mailpiece by folding the envelope sheet around the insert stack, wherein folding the envelope sheet around the insert stack forms, on a first side of the insert stack, a back of the envelope and, on a second side of the insert stack opposite the first side, a flap of the envelope and a front of the envelope; and an envelope closing system configured to close and seal the unsealed envelope by folding the flap of the envelope over the back of the envelope and adhesively sealing the flap of the envelope to the back of the envelope. an insert transport path configured to transport the one or more insert sheets (322, 324) to a merge region; a primary transport path configured to transport the envelope sheet to the merge region, wherein the insert transport path is parallel to and/or vertically above the primary transport path; an insert stager that is connected to the insert transport path and arranged proximate to the primary transport path at the merge region, wherein the insert stager is configured to receive the one or more insert sheets (322, 324) from the insert transport path in a form of an insert stack, hold the insert stack, and to dispense the insert stack onto the envelope sheet when the envelope sheet is at a first position on the primary transport path, wherein the insert stack is dispensed from the insert stager at substantially a same speed as a speed of the envelope sheet along the primary transport path; one or more adhesive applicators configured to apply an adhesive along lateral edges of a back side portion of the envelope sheet as the envelope sheet is fed into a buckle folder; a buckle folder system configured to form an unsealed envelope for the mailpiece by folding the envelope sheet around the insert stack, wherein folding the envelope sheet around the insert stack forms, on a first side of the insert stack, a back of the envelope and, on a second side of the insert stack opposite the first side, a flap of the envelope and a front of the envelope; and an envelope closing system configured to close and seal the unsealed envelope by folding the flap of the envelope over the back of the envelope and adhesively sealing the flap of the envelope to the back of the envelope.