In Old Chinese, where two or more verb phrases within a single clause (including adjectival and adverbial phrases) had to be connected by the conjunction ér or qiè, serial verb construction did not exist. In this grammatical system, it was impossible for any fusion and reanalysis across verb phrases to take place because the reanalysis had to involve a context consisting of more than one element that occurred adjacently. However, these conjunctions started to decline in Late Old Chinese and eventually died out in the first half of the Middle Chinese period, which enabled many grammatical changes to happen. Then, the first verb in a serial verb construction became grammaticalized into one of various grammatical markers.