I am writing an essay which briefly discusses linear models as well as models with fixed and random effects. I am googling since ages to find a reference which says who first introduced linear models and especially later mixed effects models. I found on wikipedia that in 1918 Ronald Fisher introduced random effects models to study the correlations of trait values between relatives. Also, as far as I can see Laird, Nan M.; Ware, James H. (1982). "Random-Effects Models for Longitudinal Data". was the first one who applied those models to longitudinal data. My data is also of type longitudinal and I therefore can use that reference later on. However, it would be great to found evidence of who first introduced linear models as wells the fixed effets models.
There is a "Brief History of LMMs" in "Linear mixed Models - A Practical Guide Using Statistical Software" (West, Welch, Galecki).
They say: "First known formulation of a one-way random-effects model" was in 1861 by Airy. Sadly there is no more precise information about the corresponding paper/book/whatever.