Introduction Current thinking is that chronic pelvic pain of unknown origin (CPPU) is poorly understood and its treatment is empirical and ineffective. According to the Integral Theory System (ITS), however, CPPU is secondary to uterosacral ligament (USL) laxity which is associated with bladder and bowel symptoms and all are potentially curable by surgical reinforcement of USLs. Material and methods We applied the ITS to anatomically explain the pathogenesis and cure of these conditions. Results The first mention of CPPU being caused by lax USLs was in the pre-WWII German literature by Heinrich Martius. CPPU was first described in the English literature in 1993 as one of the four pillars of the posterior fornix syndrome (PFS) (CPPU, urgency, nocturia and abnormal bladder emptying). Surgical cure/improvement of CPPU was achieved by shortening and reinforcing USLs initially with USL ligament plication and later with tensioned tapes because of deteriorating cure rates. Non-invasive ‘simulated operations’ which support USLs in the posterior fornix help predict USL causation. Conclusions USL tapes cure/improve CPPU, bladder and bowel dysfunctions by reinforcing the USLs against which the 3 directional forces contract. Weak suspensory ligaments may invalidate these forces to cause incontinence, emptying and pain symptoms, all of which can be potentially reversed by using tapes to reinforce the damaged ligaments, as demonstrated.