at SLAC. As late as October 1974, Cornell planned to upgrade the synchrotron to reach energies of 25 GeV and build a new synchrotron to reach 40 GeV. After the discovery of the J/Ψ in November 1974 demonstrated that interesting physics could be done with an electron-positron collider, Cornell submitted a proposal in 1975 for an electron-positron collider operating up to center-of-mass energies of 16 GeV using the existing synchrotron tunnel. An accelerator at 16 GeV would explore the energy region between that of the SPEAR accelerator and the PEP and PETRA accelerators. CESR and CLEO were approved in 1977 and mostly finished by 1979. CLEO was built in the large experimental hall at the south end of CESR; a smaller detector named CUSB (for Columbia University-Stony Brook) was built at the north interaction region. Between the proposal for and construction of CESR and CLEO, Fermilab discovered the Υ resonances and suggested that as many as three states existed. The Υ(1S) and Υ(2S) were confirmed at the DORIS accelerator. The first order of business once CESR was running was to find the Υs. CLEO and CUSB found the Υ(1S) shortly after beginning to collect data, and used the mass difference from DORIS to quickly find the Υ(2S). CESR's higher beam energies allowed CLEO and CUSB to find the more massive Υ(3S) and discover the Υ(4S). Furthermore, the presence of an excess of electrons and muons at the Υ(4S) indicated that it decayed to B mesons. CLEO proceeded to publish over sixty papers using the original CLEO I configuration of the detector. CLEO had competition in the measurement of B mesons, particularly from the ARGUS collaboration. The CLEO collaboration was worried that the ARGUS detector at DESY would be better than CLEO, therefore it began to plan for an upgrade. The improved detector would use a new drift chamber for tracking and dE/dx measurements, a cesium iodide calorimeter inside a new solenoid magnet, time of flight counters, and new muon detectors. The new drift chamber (DR2) had the same outer radius as the original drift chamber to allow it to be installed before the other components were ready. CLEO collected data for two years in the CLEO I.V configuration: new drift chamber, ten layer vertex detector (VD) inside the drift chamber, three layer straw tube drift chamber insert (IV) inside the VD, and a prototype CsI calorimeter replacing one of the