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During the last decades, an effort has been made to improve the sunspot number time-series, one of the more useful data set for space climate studies, using historical solar observations. Moreover, not only the sunspot number can be studied using these early solar records. During the last years, historical sources (i.e., sunspot drawings and solar radius measurements) have been also used to study the space climate. Here, I review some recent progress on these issues. In a hand, there are some periods with very few sunspot records and sunspot numbers are not so reliable in these intervals. I discuss the quality of sunspot records during these interesting periods: (a) 1610-1645, (b) 1721-1761, and (c) 1779-1795. On the other hand, I discuss the reliability of early sunspot drawings, sunspot position data, and solar diameter determinations to study long-term variations in our Sun. Some examples from Portuguese and Spanish historical documents are included.