Answer based on context:

In May 1918, a conservative-monarchist Senate was formed by J. K. Paasikivi, and the Senate asked the German troops to remain in Finland. 3 March 1918 Treaty of Brest-Litovsk and 7 March German-Finnish agreements bound White Finland to the German Empire's sphere of influence. General Mannerheim resigned his post on 25 May after disagreements with the Senate about German hegemony over Finland, and about his planned attack on Petrograd to repulse the Bolsheviks and capture Russian Karelia. The Germans opposed these plans due to their peace treaties with Lenin. The Civil War weakened the Finnish Parliament; it became a Rump Parliament that included only three socialist representatives. On 9 October 1918, under pressure from Germany, the Senate and Parliament elected a German prince, Friedrich Karl, the brother-in-law of German Emperor William II, to become the King of Finland. The German leadership was able to utilise the breakdown of Russia for the geopolitical benefit of the German Empire in Fennoscandia also. The Civil War and the aftermath diminished independence of Finland, compared to the status it had held at the turn of the year 1917-1918. The economic condition of Finland deteriorated drastically from 1918; recovery to pre-conflict levels was achieved only in 1925. The most acute crisis was in food supply, already deficient in 1917, though large-scale starvation had been avoided that year. The Civil War caused marked starvation in southern Finland. Late in 1918, Finnish politician Rudolf Holsti appealed for relief to Herbert Hoover, the American chairman of the Committee for Relief in Belgium. Hoover arranged for the delivery of food shipments and persuaded the Allies to relax their blockade of the Baltic Sea, which had obstructed food supplies to Finland, and to allow food into the country.

Which happened first, the formation of a Senate, or electing a German prince?
Senate was formed