The economy reacted very well at first, but into the 1970s some serious problems began to show, due in part to two-digit inflation (from 1970 and on) and to the short-term effects of the 1973 oil crisis (despite the largely unexploited oil reserves that Portugal had in its overseas territories of Angola and São Tomé and Príncipe that by 1973 were being developed at a fast pace, and were promising sources of wealth in the medium- to long-term).